Hemodynamic Assist Device

ABSTRACT

A hemodynamic flow assist device includes a miniature pump, a basket-like cage enclosing and supporting the pump, and a motor to drive the pump. The device is implanted and retrieved in a minimally invasive manner via percutaneous access to a patient&#39;s artery. The device has a first, collapsed configuration to assist in implantation and a second, expanded configuration once deployed and active. The device is deployed within a patient&#39;s aorta and is secured in place via a self-expanding cage which engages the inner wall of the aorta. The device includes a helical screw pump with self-expanding blades, sensors, and anchoring structures. Also disclosed is a retrieval device to remove the hemodynamic flow assist device once it is no longer needed by the patient and an arterial closure device to close the artery access point after implantation and removal of the hemodynamic flow assist device. The hemodynamic flow assist device helps to increase blood flow in patients suffering from congestive heart failure and awaiting heart transplant.

CROSS-REFERENCE

The present application is a continuation application of U.S. patentapplication Ser. No. 15/902,177, entitled “Hemodynamic Assist Device”and filed on Feb. 22, 2018, which relies on U.S. Patent ProvisionalApplication No. 62/462,200, of the same title and filed on Feb. 22,2017, for priority.

U.S. patent application Ser. No. 15/902,177 is also acontinuation-in-part application of U.S. patent application Ser. No.15/097,044, entitled “Arterial Closure Device”, filed on Apr. 12, 2016,and issued as U.S. Pat. No. 10,149,934 on Dec. 11, 2018, which is acontinuation application of U.S. patent application Ser. No. 13/761,544,of the same title, filed on Feb. 7, 2013, and issued as U.S. Pat. No.9,339,597 on May 17, 2016, which, in turn, relies on U.S. PatentProvisional Application No. 61/595,953, of the same title and filed onFeb. 7, 2012, for priority.

All of the abovementioned applications are hereby incorporated byreference in their entirety.

FIELD

The present specification relates generally to cardiovascular flowassist devices. More particularly, the present specification relates toan intravascular, collapsible pumping device that is implanted andremoved in a minimally invasive manner and which acts to increase bloodflow in hemodynamically compromised patients.

BACKGROUND

Heart failure is defined as a condition in which a person's heart is nolonger capable of supplying adequate blood flow to meet the needs of thebody. Congestive heart failure (CHF) refers to a condition wherein theheart does not transfer blood to end organs efficiently or it has to doso with increased filling pressures. CHF, rather than being its owndisease, occurs as a result of any one, or combination, of a number ofconditions which affect the heart, including, but not limited to,myocardial infarction, dilated cardiomyopathy, valvular heart disease,hypertension, obesity, diabetes, and cigarette smoking. All of theseconditions can lead to CHF by overloading or causing damage to the heartmuscle.

It has been estimated that nearly 5 million Americans have CHF.Increasing prevalence, hospitalizations, and deaths have made CHF amajor chronic condition in the United States and throughout the world.After the diagnosis of CHF, the death rate is 50% within 5 years. Eachyear, there are more than 400,000 new cases in the United States alone.The prevalence of CHF is increasing as the population ages.

Therapies for patients suffering from CHF include medical, surgical, andbiopharmaceutical (for example, growth factors, cytokines, myoblasts,and stem cells). Improvement in prognosis through medical therapy hasreached a ceiling. There is widespread thought that current medicaltherapies cannot be effectively expanded upon. Heart transplant is aneffective surgical remedy for patients with CHF. However, the demand faroutstrips the availability of donor hearts. Therefore, a mechanicalsolution is sorely needed to treat heart failure.

Typically for mechanical treatment of CHF, a pump such as a ventricularassist device (VAD) is implanted in a patient awaiting a hearttransplant. The VAD is implanted as a “bridge to transplant” or“destination therapy” for those weakened hearts that are expected tobecome unable to pump enough blood to sustain life. A VAD is typicallyattached to the left ventricle and draws blood from the left ventricleand sends the blood to the aorta.

A number of other devices have been proposed for assisting the diseasedheart and supporting decompensated hemodynamics. For example, U.S. Pat.No. 5,911,685, assigned to Impella Cardiosystems AG, describes “Anintravascular microaxial flow pump, comprising: a cylindrical drive unitof preselected outer diameter having an electric motor disposed thereindriving a shaft distally extending therefrom wherein such shaft issupported solely by two bearings, one located at the extreme proximalend of said drive unit and another at the extreme distal end of saiddrive unit; a cylindrical intravascular microaxial flow pump housingrigidly attached to said drive unit having essentially the samepreselected outer diameter and oriented to be coaxially and distallydisposed with respect to said drive unit; and an impeller disposedwithin said pump housing, rigidly affixed to said shaft, and locatedimmediately adjacent said distal bearing, operative to draw fluid intoand through said housing and over said drive unit.”

In addition, U.S. Pat. No. 7,125,376, assigned to Thoratec Corporation,describes “An intravascular extracardiac pumping system forsupplementing blood circulation through a patient experiencingcongestive heart failure without any component thereof being connectedto the patient's heart, the extracardiac system comprising: a pumpconfigured to pump blood through the patient at subcardiac volumetricrates, said pump having an average flow rate that, during normaloperation thereof, is substantially below that of the patient's heartwhen healthy, the pump configured to be positioned within thevasculature of a patient; an inflow conduit fluidly coupled to the pumpto direct blood to the pump, the inflow conduit configured to bepositioned within the vasculature of the patient; and an outflow conduitfluidly coupled to the pump to direct blood away from the pump, theoutflow conduit configured to be positioned within the vasculature ofthe patient; whereby the pump and the inflow and outflow conduits areconfigured so as to be inserted subcutaneously into the vasculature inan minimally-invasive procedure; and wherein the pump comprises animpeller.”

A cardiac recovery is possible for patients who suffer from CHF,especially through treatment with biopharmaceuticals. The likelihood ofcardiac recovery is believed to be increased by reducing the stress onthe heart from the decompensated state. However, the existence of a VADsurgically inserted into the heart reduces the likelihood of cardiacrecovery from CHF. The gold standard for treatment of advanced heartfailure is a heart transplant but the scarcity of transplantable heartsmakes this impossible for the vast majority of patients. Therefore,there exists a need for a hemodynamic assist device that can beimplanted and retrieved in a minimally invasive manner, without damagingthe heart and preventing cardiac recovery.

SUMMARY

The present specification discloses a retrievable intravascularhemodynamic flow assist device comprising: a pump comprising: aplurality of collapsible blades attached to a rotatable shaft; and amotor configured to coaxially rotate said shaft; a collapsible cageenclosing said pump; and an engagement mechanism configured to engagesaid pump with said cage; wherein said device has a first diameter in anundeployed configuration and a second diameter in a deployedconfiguration, wherein the second diameter is greater than the firstdiameter, wherein said blades and said cage are positioned against saidshaft when the device is in the undeployed configuration, and whereinsaid blades expand away from said shaft and said cage expands away fromsaid shaft to surround said blades when the device is in said deployedconfiguration, and wherein said engagement mechanism is configured todisengage said pump from said cage, upon activation of a releasemechanism, such that said pump is capable of being retrieved from ablood vessel of a patient while said cage remains within said bloodvessel.

Optionally, said engagement mechanism comprises at least one hook.

Optionally, said engagement mechanism is provided at a junction of saidpump with said cage.

Optionally, said cage is configured to function as a stent afterretrieval of said pump.

Optionally, said cage comprises a plurality of cage support memberscomprising a plurality of struts, proximal and distal hinge portions,and proximal and distal connectors. Optionally, each of said pluralityof struts is rectangular shaped and links one of said plurality ofproximal hinge portions with one of said plurality of distal hingeportions to allow for compression and expansion of said cage as saiddevice changes from said undeployed configuration to said deployedconfiguration. Optionally, each of said plurality of proximal connectorscomprises a first end and a second end wherein said first end and secondend are secured to proximal ends of adjacent struts of said plurality ofstruts and each of said plurality of distal connectors comprises a firstend and a second end and said first end and second end are secured todistal ends of adjacent struts of said plurality of struts to create acontiguous structure at a proximal end and a distal end of the cage.Optionally, each of said plurality of connectors is welded to each ofsaid plurality of struts. Optionally, said plurality of struts, proximaland distal hinge portions, and proximal and distal connectors are lasercut from a single Nitinol cylinder. The cage may comprise eight supportmembers.

Optionally, said release mechanism comprises a central release mechanismpositioned within said shaft and is controlled from a proximal end ofsaid shaft.

Optionally, said engagement mechanism comprises a plurality of proximalcouplers and a plurality of distal couplers configured to secure saidpump to said cage. Optionally, said shaft is elongated to release saidplurality of proximal couplers and said plurality of distal couplers.

Optionally, said intravascular hemodynamic flow assist device furthercomprises a proximal cap and a distal cap, wherein said engagementmechanism comprises a plurality of convex bevels on an outer surface ofproximal and distal ends of said struts which are configured to dislodgefrom a plurality of concave repositories inside said proximal and distalcaps when said shaft is elongated.

Optionally, said intravascular hemodynamic flow assist device furthercomprises at least one sensor and a microprocessor, wherein said atleast one sensor and microprocessor are configured to monitor datarepresentative of a shape and size of said cage in said deployedconfiguration and said microprocessor is configured to control saidmotor to adjust a shape and size of said cage based on said data.

Optionally, said cage is configured to remain in a blood vessel for aperiod up to six months after retrieval of said pump.

The present specification also discloses a retrievable intravascularhemodynamic flow assist device comprising: a retrievable helical screwpump comprising: a first shaft having a lumen, a proximal end, and adistal end, said first shaft comprising a plurality of blades forming ahelical screw pump; a second shaft having a proximal end and a distalend, wherein a portion of said proximal end of said second shaft isdisposed within, and configured to telescope into and out of, a portionsaid lumen of said first shaft at the distal end of said first shaft;and a motor positioned at said proximal end of said first shaft forcoaxially rotating said first shaft and said blades about said secondshaft to pump blood through the device; a cage enclosing said helicalscrew pump and comprising a plurality of cage support members; and anengagement mechanism configured to engage said helical screw pump withsaid cage; wherein said device has a first diameter in an undeployedconfiguration and a second diameter in a deployed configuration, whereinthe second diameter is greater than the first diameter, wherein saidplurality of blades and said plurality of cage support members arepositioned against said first shaft when the device is in the undeployedconfiguration, and wherein said blades expand away from said first shaftand said cage support members expand away from said first shaft to forma cage surrounding said blades when the device is in said deployedconfiguration, and wherein said engagement mechanism is configured todisengage said helical screw pump from said cage, upon activation of arelease mechanism, such that said helical screw pump is capable of beingretrieved from a blood vessel of a patient while said cage remainswithin said blood vessel.

The present specification also discloses a retrievable intravascularhemodynamic flow assist device comprising: a retrievable helical screwpump comprising: a first shaft having a lumen, a proximal end, and adistal end, said first shaft comprising a plurality of blades forming ahelical screw pump; a second shaft having a proximal end and a distalend, wherein a portion of said proximal end of said second shaft isdisposed within, and configured to telescope into and out of, a portionsaid lumen of said first shaft at the distal end of said first shaft;and a motor positioned at said proximal end of said first shaft forcoaxially rotating said first shaft and said blades about said secondshaft to pump blood through the device; a stent enclosing said helicalscrew pump; and an engagement mechanism configured to engage saidhelical screw pump with said stent, wherein said engagement mechanism isconfigured to disengage said pump from said stent, upon activation of arelease mechanism, such that said pump is capable of being retrievedfrom a blood vessel of a patient while said stent remains within saidblood vessel.

Optionally, said engagement mechanism comprises at least a first hookpositioned on a proximal end of said stent and at least a second hookpositioned on a distal end of said stent and wherein each of the atleast one first hook and at least one second hook is configured toengage with a plurality of recesses positioned in a proximal end of thehelical screw pump and a distal end of the helical screw pumprespectively.

Optionally, said engagement mechanism comprises a plurality of magnetsof opposing poles positioned on said stent and on said helical screwpump.

The present specification also discloses an intravascular, hemodynamicflow assist device, comprising: a miniature helical screw pump with atleast one collapsible blade; a collapsible cage structure surroundingsaid pump; and, a motor to drive said pump; wherein said devicetransforms from a first, collapsed configuration to a second expandedconfiguration, wherein the diameter of the first configuration issmaller than the diameter of the second configuration, and furtherwherein said device is converted into said first configuration duringimplantation and retrieval and converted into said second configurationfor deployment and operation.

Optionally, the intravascular hemodynamic flow assist device comprises afirst shaft having a lumen, a proximal end, and a distal end; a secondshaft having a proximal end and a distal end, wherein a portion of saidproximal end of said second shaft is disposed within, and configured totelescope into and out of, a portion of said lumen of said first shaftat the distal end of said first shaft; at least one set of pump bladesadapted to expand to an expanded configuration from a first collapsedconfiguration and collapse from the expanded configuration back to saidfirst collapsed configuration, wherein said at least one set of pumpblades is attached to said first shaft and arranged such that said firstshaft has the form of a helical screw pump; a motor attached to saidproximal end of said first shaft for coaxially rotating said first shaftand said blades about said second shaft to pump blood through thedevice; a housing encircling and containing said motor; a cap attachedto said distal end of said second shaft; a plurality of arms each havinga proximal end and a distal end, wherein said proximal end of each ofsaid plurality of arms is attached to said housing and wherein saiddistal end of each of said plurality of arms is attached to said cap;and a battery contained within said housing providing power to saidmotor, wherein said device is transformable between the first collapsedconfiguration and the expanded configuration, wherein the diameter ofthe first collapsed configuration is smaller than the diameter of thesecond expanded configuration, wherein said blades and said arms arecompressed against said first shaft when the device is in the firstcollapsed configuration, and wherein said blades expand away from saidfirst shaft and said arms expand away from said first shaft to form acage surrounding said blades when the device is in said expandedconfiguration.

Optionally, the hemodynamic flow assist device further comprises a wireattached to said motor, wherein said wire provides power and/or controlfrom a power and/or control device external to a patient. The blades andportions of said arms comprise a shape memory metal. The shape memorymetal is Nitinol. The hemodynamic flow assist device further comprises acoupling positioned between said proximal end of said first shaft andsaid motor for transferring rotation to said first shaft.

Optionally, the hemodynamic flow assist device further comprises atleast one sensor for sensing a functional parameter of said deviceand/or a physiological parameter of a patient, wherein data from saidsensor is transmitted to a controller and wherein said controller usessaid data to control said device. The hemodynamic flow assist devicefurther comprises at least one camera. The hemodynamic flow assistdevice further comprises a mechanism for changing a size of said cagebased on the size of a patient's aorta. The first shaft furthercomprises a plurality of compression rings to allow for deformation ofthe first shaft during placement.

Optionally, the hemodynamic flow assist device further comprises acompressible tubular cylinder having a lumen for directing blood flowinto said device, wherein said cylinder is positioned within said cageand is attached to said second shaft by at least one strut, furtherwherein said cylinder is compressed against said first shaft when saiddevice is in said first collapsed configuration. The hemodynamic flowassist device further comprises a self-charging battery or inverter,wherein said self-charging battery is charged by the unassisted flow ofblood turning said blades when a patient having said device implanted isin the resting position.

Optionally, the hemodynamic flow assist device further comprises anaccelerometer, wherein said accelerometer detects a position of apatient and generates data indicative of said position, and wherein acontroller receives said data and causes a rotational speed of thedevice to adjust accordingly. The cage has a cone shape configured toresist dislodgement within a patient's aorta.

Optionally, an intravascular hemodynamic flow assist device comprises: afirst shaft having a lumen, a proximal end, and a distal end; a secondshaft having a proximal end and a distal end, wherein a portion of saidproximal end of said second shaft is disposed within, and configured totelescope into and out of, a portion said lumen of said first shaft atthe distal end of said first shaft; at least one set of collapsible pumpblades attached to said first shaft, said blades arranged such that saidfirst shaft forms a helical screw pump; a motor attached to saidproximal end of said first shaft for coaxially rotating said first shaftand said at least one set of collapsible blades about said second shaftto pump blood through the device; a housing encircling and containingsaid motor; a cap attached to said distal end of said second shaft; anelongate, collapsible tubular cylinder having a lumen, a proximal end,and a distal end, wherein said cylinder is attached to said second shaftby a plurality of struts; and, a battery contained within said housingproviding power to said motor.

Optionally, an intravascular hemodynamic flow assist device comprises afirst shaft having a lumen, a proximal end, and a distal end; a secondshaft having a proximal end and a distal end, wherein a portion of saidproximal end of said second shaft is disposed within, and configured to,telescope into and out of, a portion said lumen of said first shaft atthe distal end of said first shaft; a first bearing coupled to andcoaxially rotatable about said proximal end of said first shaft; asecond bearing coupled to and coaxially rotatable about said distal endof said second shaft; at least one set of collapsible pump bladesattached at a first end to said first bearing and at a second end tosaid second bearing, said blades arranged such that said first shaft andsecond shafts form a helical screw pump; a housing attached to saidproximal end of said first shaft; a cap attached to said distal end ofsaid second shaft; and, a plurality of arms each having a proximal endand a distal end, wherein said proximal end of each of said plurality ofarms is attached to said housing and wherein said distal end of each ofsaid plurality of arms is attached to said cap; wherein portions of saidarms are magnetically charged and cause said blades to spin via magneticcoupling; wherein said device is transformable between a first,collapsed configuration and a second expanded configuration, wherein thediameter of the first configuration is smaller than the diameter of thesecond configuration, further wherein said device is converted into saidfirst configuration during implantation and retrieval and converted intosaid second configuration for deployment and operation, further whereinsaid second shaft partially telescopes distally out of said first shaftand said blades and said arms are compressed against said first shaftwhen the device is in said first configuration, further wherein saidsecond shaft partially telescopes proximally into said first shaft, saidblades expand away from said first shaft, and said arms expand away fromsaid first shaft to form a cage surrounding said blades when the deviceis in said second configuration, still further wherein said arms contactan inner wall of an aorta to hold the device in place.

The present specification also discloses a method of implanting thehemodynamic flow assist devices disclosed above, where the methodcomprises: providing a tubular sheath having a lumen, a proximal end, adistal end, and a guide wire disposed within said lumen; creating anaccess point into an artery of a patient; inserting said sheath and wireinto said artery and advancing it such that said distal end of saidsheath is positioned within said patient's descending aorta; insertingsaid flow assist device, in said first configuration, into said sheathand advancing it along said guide wire to said distal end of saidsheath; providing a positioning device comprising an elongate flexibleshaft having a proximal end and a distal end, wherein said distal end iscoupled to said housing of said flow assist device and said proximal endis manipulated by a physician; using said positioning device to advancesaid flow assist device beyond said distal end of said sheath and toposition said flow assist device within said patient's aorta, whereinsaid flow assist device passively expands from said first configurationto said second configuration once it is beyond said distal end of saidsheath; uncoupling said positioning device from said flow assist deviceand removing said positioning device and said sheath from said aorta viasaid artery; and, closing said access point in said artery.

Optionally, the artery is any one of a femoral, external iliac, commoniliac, subclavian, brachial, and axillary artery. The flow assist deviceis positioned within said descending aorta between a left subclavianartery and a point distal a renal artery.

The specification also discloses a blood vessel closure devicecomprising: an elongate tubular sheath having a sheath lumen, a proximalend, and a distal end; an elongate tamper tool disposed within saidsheath lumen and having a tool lumen, a proximal end, and a distal endwherein said distal end of said tool is positioned proximate and withinsaid distal end of said sheath and said proximal end of said toolextends beyond said proximal end of said sheath, further wherein saidtool includes a handle at said proximal end; and a pair of compressiblediscs positioned within said distal end of said sheath distal to and incontact with said distal end of said tool, said discs connected by acenter member and transformable between a first configuration and asecond configuration, wherein said discs are compressed and have atubular shape when in said first configuration and are expanded and havean umbrella shape when in said second configuration, further whereinsaid discs are deployable beyond said distal end of said sheath bypushing on said handle of said tool such that said tool moves distallyinto said sheath and pushes out said discs; further wherein said discsare in said first configuration when disposed within said sheath and arein said second configuration when advanced beyond said distal end ofsaid sheath; wherein, when said discs are deployed in said secondconfiguration, a first distal disc is positioned within a blood vesseland a second proximal disc is positioned outside the blood vessel withthe center member occluding an opening in a wall of said blood vessel.

The present specification also discloses a method of closing an openingin a blood vessel wall using the closure device disclosed above, wherethe method comprises the steps of: providing a guide wire having aproximal end and a distal end; inserting a said distal end of said guidewire into said blood vessel through said opening; inserting saidproximal end of said guide wire into said tool lumen and advancing saidclosure device along said guide wire; positioning said distal end ofsaid sheath in the interior of said blood vessel; pushing on said handleof said tool of said closure device to advance a distal disc beyond saiddistal end of said sheath, said distal disc passively expanding intosaid second configuration within said blood vessel; pulling back on saidclosure device to position said distal disc against an inner wall ofsaid blood vessel; pushing on said handle of said tool of said closuredevice to advance a proximal disc beyond said distal end of said sheath,said proximal disc passively expanding into said second configurationoutside of said blood vessel and resting against an outer wall of saidblood vessel such that the distal and proximal discs and center memberact to occlude said opening in said blood vessel; and, removing saidsheath with said tool and said guidewire.

Optionally, the method further comprises removing from the patient saidsecond shaft, said at least one set of pump blades, said motor, batteryand said cap; and keeping said plurality of arms, wherein said pluralityof arms are configured to function as a stent.

Optionally, the intravascular hemodynamic flow assist device may furthercomprise at least one of a camera and a sensor. Optionally, said sensoris at least one of an accelerometer sensor, a flow meter sensor, and anEKG sensor. Optionally, said accelerometer generates activity data andwherein a rotational speed of said motor is modulated based upon saidactivity data. Optionally, said flow meter generates data indicative ofblood flow and wherein a rotational speed of said motor is modulatedbased upon said data indicative of blood flow.

Optionally, said battery is configured to be charged by a movement ofsaid at least one set of pump blades caused by a flow of blood when themotor is off.

Optionally, the intravascular hemodynamic flow assist device may furthercomprise hooks on said plurality of arms to resist dislodgement within apatient's aorta.

Optionally, the intravascular hemodynamic flow assist device may furthercomprise a bifurcated anchor to resist dislodgement within a patient'saorta, wherein said bifurcated anchor comprises two arms and whereineach arm is configured to respectively sit within each branch of anaortic bifurcation.

The aforementioned and other embodiments of the present specificationshall be described in greater depth in the drawings and detaileddescription provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will befurther appreciated, as they become better understood by reference tothe detailed description when considered in connection with theaccompanying drawings:

FIG. 1 is an oblique front view illustration of one embodiment of thecardiovascular flow assist device in the expanded, deployedconfiguration;

FIG. 2 is an oblique, cross-sectional illustration of an aorta depictingone embodiment of the cardiovascular flow assist device in the expanded,deployed configuration positioned therein;

FIG. 3 is an oblique front view illustration of one embodiment of thecardiovascular flow assist device in the collapsed, deliverableconfiguration;

FIG. 4A is an oblique, front view illustration depicting one embodimentof a cardiovascular flow assist device in the expanded, deployedconfiguration side by side with another cardiovascular flow assistdevice in the collapsed, deliverable configuration;

FIG. 4B is a side view illustration depicting the same embodiment of acardiovascular flow assist device in the expanded, deployedconfiguration side by side with another cardiovascular flow assistdevice in the collapsed, deliverable configuration, of FIG. 4A;

FIG. 5A is a side view illustration of one embodiment of thecardiovascular flow assist device in the expanded, deployedconfiguration, depicting two cage support members removed from eitherside of the helical screw pump;

FIG. 5B is an oblique, side view illustration of one embodiment of anouter shaft portion blade attachment segment, with one attached blade,of the cardiovascular flow assist device;

FIG. 6A is an oblique, front view illustration of one embodiment of thehelical screw pump of the cardiovascular flow assist device, depictingtwo sets of helical blades in the expanded configuration;

FIG. 6B is a side view illustration of the same embodiment of thehelical screw pump of the cardiovascular flow assist device, depictingtwo sets of helical blades in the expanded configuration, of FIG. 6A;

FIG. 7A is an oblique, front view illustration of one embodiment of thehelical screw pump of the cardiovascular flow assist device in theexpanded configuration, depicting one set of helical blades;

FIG. 7B is a side view illustration of the same embodiment of thehelical screw pump of the cardiovascular flow assist device, depictingone set of helical blades in the expanded configuration, of FIG. 7A;

FIG. 7C is a front-on view illustration of the same embodiment of thehelical screw pump of the cardiovascular flow assist device, depictingone set of helical blades in the expanded configuration, of FIG. 7A;

FIG. 8A is an oblique, front view illustration of one embodiment of thehelical screw pump of the cardiovascular flow assist device, depictingone set of helical blades in the collapsed configuration;

FIG. 8B is a side view illustration of the same embodiment of thehelical screw pump of the cardiovascular flow assist device, depictingone set of helical blades in the collapsed configuration, of FIG. 8A;

FIG. 8C is a front-on view illustration of the same embodiment of thehelical screw pump of the cardiovascular flow assist device, depictingone set of helical blades in the collapsed configuration, of FIG. 8A;

FIG. 9A is an oblique, front view illustration of one embodiment of twocage support members formed together into a singular cage arm in theexpanded configuration;

FIG. 9B is a side view illustration of the same embodiment of two cagesupport members formed together into a singular cage arm in the expandedconfiguration of FIG. 9A;

FIG. 9C is a top-down view illustration of the same embodiment of twocage support members formed together into a singular cage arm in theexpanded configuration of FIG. 9A;

FIG. 9D is a front-on view illustration of the same embodiment of twocage support members formed together into a singular cage arm in theexpanded configuration of FIG. 9A;

FIG. 10A is an oblique, front view illustration of one embodiment offour cage arms combined together to form a complete basket-like cage inthe expanded configuration;

FIG. 10B is a side view illustration of the same embodiment of four cagearms combined together to form a complete basket-like cage in theexpanded configuration of FIG. 10A;

FIG. 10C is a front-on view illustration of the same embodiment of fourcage arms combined together to form a complete basket-like cage in theexpanded configuration of FIG. 10A;

FIG. 11A is an oblique, front view illustration of one embodiment offour cage arms combined together to form a complete basket-like cage inthe collapsed configuration;

FIG. 11B is a side view illustration of the same embodiment of four cagearms combined together to form a complete basket-like cage in thecollapsed configuration of FIG. 11A;

FIG. 11C is a front-on view illustration of the same embodiment of fourcage arms combined together to form a complete basket-like cage in thecollapsed configuration of FIG. 11A;

FIG. 12A is a side view illustration on one embodiment of an arterialclosure device, depicting the arterial closure discs of the devicepositioned within a delivery sheath;

FIG. 12B is a side view illustration of the same embodiment of thearterial closure device of FIG. 12A, depicting the distal arterialclosure disc expanded and deployed from the distal end of the deliverysheath;

FIG. 12C is a side view illustration of the same embodiment of thearterial closure device of FIG. 12A, depicting both the distal andproximal arterial closure discs expanded and deployed from the distalend of the delivery sheath;

FIG. 12D is a side view illustration of one embodiment of the arterialclosure discs fully deployed with the delivery sheath removed;

FIG. 12E is an illustration of one embodiment of the arterial closurediscs, depicting the struts used to expand the discs to their deployedconfiguration;

FIG. 13 is a flowchart illustrating the steps involved in implanting thehemodynamic flow assist device in the descending aorta of a patient, inaccordance with one embodiment of the present specification;

FIG. 14 is a flowchart illustrating the steps involved in closing anarterial access point using the arterial closure device, in accordancewith one embodiment of the present specification;

FIG. 15A illustrates an embodiment of a cardiovascular flow assistdevice, at a first stage, when converting from an initial collapsed,deliverable configuration to various expanded, deployed configurations;

FIG. 15B illustrates an embodiment of a cardiovascular flow assistdevice, at a second stage, when converting from an initial collapsed,deliverable configuration to various expanded, deployed configurations;

FIG. 15C illustrates an embodiment of a cardiovascular flow assistdevice, at a third stage, when converting from an initial collapsed,deliverable configuration to various expanded, deployed configurations;

FIG. 15D illustrates an embodiment of a cardiovascular flow assistdevice, at a fourth stage, when converting from an initial collapsed,deliverable configuration to various expanded, deployed configurations;

FIG. 15E illustrates an embodiment of a cardiovascular flow assistdevice, at a fifth stage, when converting from an initial collapsed,deliverable configuration to various expanded, deployed configurations;

FIG. 15F illustrates an embodiment of a cardiovascular flow assistdevice, at a sixth stage, when converting from an initial expanded,deployed configuration to various collapsed configurations;

FIG. 15G illustrates an embodiment of a cardiovascular flow assistdevice, at a seventh stage, when converting from an initial expanded,deployed configuration to various collapsed configurations;

FIG. 15H illustrates an embodiment of a cardiovascular flow assistdevice, at an eighth stage, when converting from an initial expanded,deployed configuration to various collapsed configurations;

FIG. 15I illustrates an embodiment of a cardiovascular flow assistdevice, at a ninth stage, when converting from an initial expanded,deployed configuration to various collapsed configurations;

FIG. 15J illustrates an embodiment of a cardiovascular flow assistdevice, at a tenth stage, when converting from an initial expanded,deployed configuration to various collapsed configurations;

FIG. 15K illustrates an embodiment of a cardiovascular flow assistdevice, at an eleventh stage, when converting from an initial expanded,deployed configuration to various collapsed configurations;

FIG. 16A illustrates a direction of flow of electrical power between thepump and battery at different times;

FIG. 16B illustrates a direction of flow of electrical power between thepump and battery at different times;

FIG. 17A illustrates an anchoring mechanism in the form of a cone-shapedcage and hooks on the distal end of cage supporting members to resistdislodgement within a patient's aorta, in accordance with an embodimentof the hemodynamic flow assist device of the present specification;

FIG. 17B illustrates yet another embodiment of an anchoring mechanismwhere the proximal end of the hemodynamic flow assist device includes abifurcated anchor to resist dislodgement within a patient's aorta;

FIG. 18A illustrates the operation of exemplary engagement and releasemechanisms to separate the cage from the remaining device, in accordancewith an embodiment of the present specification;

FIG. 18B illustrates the operation of exemplary engagement and releasemechanisms, also shown in FIG. 19A, to separate the cage from theremaining device, in accordance with an embodiment of the presentspecification;

FIG. 19A illustrates an exemplary embodiment of a cage within an aortaintegrated with a pump and other components of the hemodynamic flowassist device;

FIG. 19B illustrates an exemplary embodiment of the hemodynamic flowassist device showing an engagement mechanism and a release mechanism inoperation to release the cage;

FIG. 19C illustrates an exemplary embodiment of the hemodynamic flowassist device showing the cage separated from the other components;

FIG. 19D illustrates an exemplary embodiment of the cage, retainedwithin the vessel and having only the pump removed;

FIG. 20A illustrates an aortic stent with internal hooks, in accordancewith an embodiment of the present specification;

FIG. 20B illustrates a device anchored within the aortic stent withinternal hooks of FIG. 20A, in accordance with an embodiment of thepresent specification;

FIG. 21A illustrates an exemplary configuration of a hemodynamic flowassist device deployed in an aorta that allows access for other devices,in accordance with an embodiment of the present specification; and

FIG. 21B illustrates another exemplary configuration of a hemodynamicflow assist device deployed in aorta that allows access for otherdevices, in accordance with an embodiment of the present specification.

DETAILED DESCRIPTION

The present specification is directed toward an intravascular,collapsible pumping device that is implanted and removed in a minimallyinvasive manner and which acts to increase blood flow in hemodynamicallycompromised patients. The device is positioned within the aorta,downstream of the aortic arch, and offloads the diseased heart byincreasing systemic blood flow. In one embodiment, the device is anelongate, cylindrically-shaped device with a proximal end and a distalend, comprising a miniature pump, a basket-like cage enclosing saidpump, and a motor to drive the pump. In one embodiment, power for themotor is supplied by an internal battery. In another embodiment, atleast one wire extends from the proximal end of the device and providespower to the device. Optionally, in one embodiment, the wire alsoprovides control for the device. In another embodiment a wireless RadioFrequency (RF) system is embedded within the device for wirelesselectromagnetic powering of the device.

In one embodiment, the device includes a cap at its distal end. In oneembodiment, the pump is a helical screw pump, such as an Archimedes'pump, comprising a rotating shaft with at least one set of collapsiblepump blades attached thereto. In one embodiment, the rotating shaftcomprises an inner portion and an outer portion, wherein the innerportion is capable of slidable movement partially into and out of theouter portion. In one embodiment, preloaded compression separating ringson the shaft provide fluid tight seals and allow for any axialdisplacement introduced by flexible coupling and pressure on the pumpblades. The cage is comprised of a multitude of support members andprovides support to the pump and anchors the pump within the descendingaorta. The pump blades and portions of the cage support members arecomposed of a shape memory metal that allows the device to change from afirst, deliverable and collapsed configuration into a second, deployedand expanded configuration. In one embodiment, the pump blades andportions of each support member are composed of Nitinol. In oneembodiment, as the device is collapsed, the inner portion of therotating shaft extends partially from the outer portion, causing thedevice to become elongated when in the collapsed configuration. At thesame time, the pump blades and cage support members collapse in towardthe center of the device, resulting in the total diameter of the devicebeing decreased while in the collapsible configuration.

In one embodiment, the intravascular, collapsible pumping device of thepresent specification includes at least one sensor. In one embodiment,the sensor is a full 3D space profile pressure quad-sensor. In anotherembodiment, the sensor is an inflow quad-sensor. In another embodiment,the sensor is a temperature and outflow quad-sensor. The sensor is usedto relay information regarding the initial positioning and initialaortic wall proximity, based on differentials of comparable sensor pairsat any stage of the device. In one embodiment, the sensor provides thehealth care professional with vital device functionality information. Inanother embodiment, the device includes two or more sensors positionedat different locations along the length of the device. In oneembodiment, a first sensor is positioned proximate the distal end of thedevice and a second sensor is positioned proximate the proximal end ofthe device. Differences in values measured between the first sensor andthe second sensor are used to determine rates of flow and functionalityof the device. In one embodiment, the intravascular, collapsible pumpingdevice of the present specification includes at least one camera. In oneembodiment, the camera is positioned proximate the distal end of thedevice. In one embodiment, the camera is an infra-red (IR) chargedcoupled device (CCD) camera.

In one embodiment, the device is implanted percutaneously through apatient's artery. In one embodiment, the device is introduced via thefemoral artery. In another embodiment, the device is introduced via theexternal iliac artery. In another embodiment, the device is introducedvia the common iliac artery. In yet another embodiment, the device isintroduced via the axillary or subclavian artery. In one embodiment, apuncture is made in the patient's thigh area and a sheath is introducedinto the femoral artery and its distal end is positioned in the aorta.The device is mechanically inserted into the sheath. The sheath has adiameter that is smaller than the diameter of the device in its expandedconfiguration and is larger than the diameter of the device in itscollapsed configuration. In one embodiment, the act of inserting thedevice into the sheath causes the device to compress into its collapsedconfiguration. The sheath and collapsed device are advanced into thepatient's aorta to the desired deployment location. In one embodiment,the device is deployed in the descending aorta just downstream from theleft subclavian artery. In another embodiment, the device is deployed inthe descending aorta just downstream from the renal arteries. In variousother embodiments, the device is deployed anywhere along the descendingaorta between the left subclavian artery and just downstream from therenal arteries, with care taken not to occlude any branches containedtherewithin. In various other embodiments, access is obtained throughthe subclavian, axillary or brachial or radial arteries.

Once the sheath and device have reached the desired deployment location,the sheath is retracted while the device is held in place by an attachedpositioning shaft. The positioning shaft is an elongate, flexible, solidshaft having a proximal end and a distal end. The distal end of theshaft attaches to the proximal end of the device with either a screw orclip and the shaft traverses the entire length of the sheath. Theproximal end of the shaft exits from the proximal end of the sheath andincludes a proximal knob that can be manipulated outside the sheath. Theshaft is detached from the device via an unlock mechanism after thedevice is positioned appropriately. In one embodiment, once the sheathhas cleared the device, the pump blades and cage support members expandand the inner portion of the rotating shaft telescopes partly into theouter portion of said shaft. In another embodiment, a distal portion ofthe rotating shaft extends partially into the distal cap when in theexpanded configuration. In this embodiment, the distal cap comprises afluid filled cavity to accommodate a distal portion of the rotatingshaft. The fluid is eliminated when the cage expands. As the devicechanges into its deployed, expanded configuration, its length shortensand diameter increases. The cage support members come to rest upon thewalls of the aorta and the rotating shaft with attached pump blades isfree to spin within the cage. The positioning shaft is disengaged fromthe proximal end of the device and removed from the sheath. The sheathis then removed from the patient. In an embodiment in which the devicehas an internal battery, the puncture site is sutured close. In analternate embodiment, in which the device includes a power and/orcontrol wire, said wire extends from the puncture site and is secured atthe patient's skin. In one embodiment, the wire extends to a batteryand/or control pack which sits in a belt or vest at the belt level.

The present specification is also directed toward a retrieval deviceused to remove the pumping device from the patient's aorta. In oneembodiment, the retrieval device is similar to the one described in U.S.Pat. No. 7,878,967, entitled “Heart Failure/Hemodynamic Device” andassigned to the applicant of the present invention, which is herebyincorporated in its entirety. In one embodiment, when the pumping deviceis ready to be removed, a sheath is once again introduced percutaneouslyinto the femoral artery using the power and/or control wire, ifremaining. In another embodiment, the control and the power wirescomprise at least two separate wires coming from diagonally oppositeends of the proximal portion of the device. The removal device is theninserted into the sheath and both are advanced through the vasculatureinto the descending aorta and up to the pumping device. The retrievaldevice is then advanced further beyond the end of the sheath. The distalend of the retrieval device interfaces with the proximal end of thepumping device such that the pumping device becomes connected to theretrieval device. This connection can be a mechanical locking mechanismor magnetically assisted. The retrieval device is then retracted backinto the sheath, bringing the pumping device with it. The attachedproximal wires and enclosing wires jacket that, in one embodiment, isreinforced for added strength can be used to pull the device into thesheath. As the cage comes into contact with the sheath, the supportmembers are compressed back toward the center of the pumping device.Compression of the cage causes the inner portion of the rotating shaftto partially extend out from the outer portion of said rotating shaft.In another embodiment, wherein the distal cap comprises a cavity tohouse a distal portion of the shaft, the distal cap extends away fromthe shaft and said cavity fills with blood during retrieval. In oneembodiment, as the cage gradually collapses, the shaft with helical pumpblades rotates reversely. The initial blade shape and the fully expandedblade shape are developed with a blade profile such that when rotatedreversely allow the blades to be deformed and take a similar shape as inthe insertion stage. In one embodiment, the inner construction anddetails of the enclosed cage will provide further support and guidanceto the pump blades to assist in their deformation and effectively placethem in the inside space of the compressed cage. Compression of the cagesupport members and extension of the rotating shaft inner portion resultin collapse of the helical pump blades. Pulling of the pumping deviceinto the sheath via the attached retrieval device causes the pumpingdevice to revert back to its collapsed, retrievable configuration. Oncefully withdrawn into the sheath, the pumping device, along with theattached retrieval device and sheath, is removed through the femoralartery and the access site is sutured closed. In one embodiment, asieve-like filter is attached to the distal end of the retrieval device.This circular filter is deployed when the retrieval device is extendedbeyond the distal end of the sheath. The filter traps any debris that isdislodged in the process of retrieving the pumping device. The filterthen also collapses into the sheath along with the device after thedevice is retracted into the sheath.

In one embodiment, retrieval of the device employs two wires attached tothe proximal end of the pumping device. A retrieval device is insertedinto the access vessel using the two wires as rails to guide theretrieval device to the pumping device. In one embodiment, the wires canbe used to elongate the shaft of the pumping device when put on tension,thereby collapsing the device prior to retrieval.

In another embodiment, wherein the pumping device includes an internalbattery and no wires extend from the body of the patient, retrieval ofthe device employs magnetism. The proximal end of the pumping device andthe distal end of the retrieval device are magnetized with oppositepolarities so that the two will connect when the retrieval device isadvanced to the deployed pumping device.

Optionally, in one embodiment, the rotating shaft of the pump iscomprised of a stretchable material rather than inner and outerportions. When the device is collapsed, the shaft stretches, increasingthe length of the device. Once released from the insertion sheath, theshaft contracts to its default shape. In this embodiment, the at leastone set of blades is attached only at the proximal and distal ends ofthe shaft. As the shaft is stretched, the blades and cage supportmembers stretch and compress toward the center of said shaft. As theshaft contracts to its default shape, the blades return to theiroperable, expanded configuration.

Optionally, in one embodiment, the at least one set of blades isattached only to bearings positioned at the proximal and distal ends ofthe shaft. In this embodiment, only the blades rotate with the bearings.In one embodiment, the blades are rotated via magnetic coupling. Theshaft does not rotate, resulting in fewer moving parts and lower powerconsumption. This embodiment can be utilized on a telescoping shaft or astretchable shaft as described above.

Optionally, in one embodiment, the basket-like cage acts as a stator androtates the blades such that the entire helical blade set(s) and cageare magnetically active and become a rotor of the coreless motor,eliminating the need for an electric motor at the proximal end of thedevice. In this embodiment, the blades are composed of a magnetic fieldmaterial and the cage components possess the ability to electricallyinduce a polarized magnetic field.

Optionally, in one embodiment, the device includes a collapsible,continuous cylinder positioned just within the cage. The cylinder isopen at its distal and proximal ends to allow for the passage of blood.The space between the blades of the pump and the cylinder is minimal,improving the efficiency of the device by decreasing the amount ofleakage around the blades. In one embodiment, the blades and thecylinder are like charged so that the cylinder would be magneticallylevitated and not come into contact with the blades.

Optionally, in one embodiment, the device includes a collapsible,continuous cylinder in place of the basket-like cage. The cylinder isopen at its distal and proximal ends to allow for the passage of blood.The outside circumference of the cylinder rests upon the inner wall ofthe aorta. In one embodiment, the cylinder is attached to the device viacollapsible struts. The space between the blades of the pump and thecylinder is minimal, improving the efficiency of the device bydecreasing the amount of leakage around the blades.

Optionally, in one embodiment, the device includes a mechanism to adjustthe diameter of the device in the deployed configuration dependent uponthe size of the patient's aorta. In one embodiment, the power/controlwire leading from the proximal end of the device enables the physicianto dial in the cage diameter by extending or retracting the inner shaftportion within the outer shaft portion.

Optionally, in one embodiment, the device is designed in a manner suchthat when in the expanded configuration, said device takes on a slightlyelliptical shape in which the proximal end is slightly smaller indiameter than the distal end. Such a design provides at least twobenefits. First, the device sits in the aorta like a cone, resistingmigration caused by the constant blood flow and forward pressureexperienced by the device. Second, the device is easier to retrieve asit fits more easily back into the sheath.

Optionally, in one embodiment, magnetic coupling is used between themotor and the pump with the motor parts being hermetically sealed sothat no fluid seepage can occur.

Optionally, in one embodiment, the device includes a self-chargingbattery in its proximal end. In this embodiment, the device includes aninverter. While the patient is at rest or in prone position, and thedevice is not in use, inertia and momentum caused by the blood flowgenerated by the heart continues to rotate the blades and is stored asenergy for use when the device is in operation.

Optionally, in one embodiment a wireless Radio Frequency (RF) system isused for wireless electromagnetic powering of the device.

Optionally, in one embodiment, the device includes an accelerometer todetect increased movement by the patient, signifying increased physicalactivity. Based on the heightened physical activity, the deviceincreases blood flow to meet demands. Conversely, if the accelerometerdetects decreased physical activity, the device will decrease bloodflow. In another embodiment, the device includes a flow meter. The flowmeter will detect increased blood flow from the heart during heightenedphysical activity and the device will in turn increase speed andtherefore blood flow. In one embodiment, the flow meter sends data tothe patient via the cable attached to the proximal end of the device.The patient can then increase or decrease blood flow provided by thedevice based upon values obtained from the flow meter.

Optionally, in one embodiment, the distal end cap includes a mechanismthat assists in the transformation of the device from the collapsedconfiguration into the deployed configuration. The distal cap is hollowand contains a biocompatible fluid that is used to provide hydraulics tochange the device between collapsed and expanded shapes.

The device of the present specification increases blood flow to the bodyparts located downstream of said device, thereby decreasing strain uponthe diseased heart. As demand on the heart is lessened, the heart muscleis able to rest and, over time, partially repair itself. In oneembodiment, the helical screw pump of the device spins at a variablerate that is fully controlled in a closed loop via a monitoring andcontrolling computer. In one embodiment, the helical screw pump of thedevice spins at a rate within a range of 100 to 10,000 rpms. The lowerspeed allows for greater energy efficiency and decreased red blood celldestruction caused by the pump. In one embodiment, at least anadditional 2.5 L/min of blood flow is provided by the device of thepresent specification. In various embodiments, additional blood flowgreater than the amount of 2.5 L/min, and greater than that provided bya normally functioning heart at rest (about 5 L/min) are provided by thedevice of the present specification. Without assistance, the compromisedheart would not be able to sustain adequate blood flow to the body,resulting in continual worsening of heart failure, eventually leading todeath of the patient.

The present specification is also directed toward an arterial closuredevice used to close the access point in the artery followingimplantation or removal of the pumping device. In one embodiment, thearterial closure device comprises a sheath having a lumen, a proximalend, and a distal end. Disposed within the distal end of the sheath is apair of arterial closure discs connected by a center member. When in thesheath, the discs are compressed into a tubular configuration. A tampertool having a proximal end and a distal end extends within the lumen ofthe sheath. The proximal end of the tamper tool includes a handle andthe distal end abuts the proximal disc of the pair of arterial closurediscs. A physician places the distal end of the sheath in the arterythrough the access site. The physician then pushes on the handle of thetamper tool which causes the distal disc to extend beyond the distal endof the sheath and into the artery. As the distal disc extends, itexpands into an umbrella shape. The physician then pulls back on thedevice such that the distal disc abuts the inner wall of the artery.Pushing again on the handle extends the proximal disc beyond the distalend of the sheath. The proximal disc also expands into an umbrella shapeand comes to rest on the outer wall of the artery, effectively closingthe arterial access site.

The present invention is directed toward multiple embodiments. Thefollowing disclosure is provided in order to enable a person havingordinary skill in the art to practice the invention. Language used inthis specification should not be interpreted as a general disavowal ofany one specific embodiment or used to limit the claims beyond themeaning of the terms used therein. The general principles defined hereinmay be applied to other embodiments and applications without departingfrom the spirit and scope of the invention. Also, the terminology andphraseology used is for the purpose of describing exemplary embodimentsand should not be considered limiting. Thus, the present invention is tobe accorded the widest scope encompassing numerous alternatives,modifications and equivalents consistent with the principles andfeatures disclosed. For purpose of clarity, details relating totechnical material that is known in the technical fields related to theinvention have not been described in detail so as not to unnecessarilyobscure the present invention.

In the description and claims of the application, each of the words“comprise” “include” and “have”, and forms thereof, are not necessarilylimited to members in a list with which the words may be associated. Itshould be noted herein that any feature or component described inassociation with a specific embodiment may be used and implemented withany other embodiment unless clearly indicated otherwise.

FIG. 1 is an oblique front view illustration of one embodiment of thecardiovascular flow assist device 100 in the expanded, deployedconfiguration. In the pictured embodiment, the device 100 includes twosets of helical pump blades 104. Each blade 104 includes a multitude ofsmall fenestrations 105. These fenestrations 105 impart increasedflexibility to each blade 104 so that the blades will be easier tocompress without sacrificing efficiency of the pump. Each blade 104 isconnected to a portion of the rotating pump shaft, which is not easilyvisualized in this figure but is further discussed with reference toFIGS. 5A-6B. A cable 108 extends from the proximal end of the device 100and, in various embodiments, carries power supply and/or control wiresfrom outside the body to the device 100. The device 100 includes eightcage support members 120 encircling the pump. In one embodiment, twosupport members 120 are manufactured together in one piece to assist inassembly of the device, as will be further discussed with reference toFIGS. 9A-9D. In one embodiment, the device 100 includes a cap 106 at itsdistal end. In one embodiment, the distal end cap 106 is cone shaped. Inthe pictured embodiment, the distal end cap 106 includes four sensors132 positioned equidistant from one another proximate the distal tip ofsaid end cap 106. Four additional sensors 134 are positioned proximatethe distal end of every second cage support member 120, such that everysupport member 120 containing a sensor is adjacent to a support member120 without a sensor. Each support member 120 containing a distal endsensor 134 also has an additional sensor 136 proximate its proximal end,resulting in a total of twelve sensors on the device 100. Althoughtwelve sensors are depicted in the pictured embodiment, any number ofsensors may be used to provide the health care professional informationregarding the functionality of the device 100. Data gathered by thesensors is transferred to a processor outside the patient via cable 108.

FIG. 2 is an oblique, cross-sectional illustration of an aorta 240depicting one embodiment of the cardiovascular flow assist device 200 inthe expanded, deployed configuration positioned therein. When deployed,the diameter of the cage of the device 200 is slightly larger than theinternal diameter of the aorta, such that the cage support members 220contact the inner wall of the aorta. Each cage support member 220becomes fixed in place against the aortic wall, securing the device 200within the aorta 240. The pump is then free to rotate within the supportcage, increasing blood flow downstream from the device 200.

FIG. 3 is an oblique front view illustration of one embodiment of thecardiovascular flow assist device 300 in the collapsed, deliverableconfiguration. In the pictured embodiment, the device 300 includes adistal end cap 306 with sensors 332 and a power/control cable 308emanating from its proximal end. The cage support members 320 arecollapsed in toward the center of the device 300, forming an elongate,streamlined cylindrical shape. This collapsed configuration enables thephysician to implant the device in a percutaneous fashion, avoiding amore invasive surgical procedure and resulting in less stress anddiscomfort to the patient.

FIGS. 4A and 4B are oblique front and side illustrations, respectively,depicting one embodiment of a cardiovascular flow assist device 400 inthe expanded, deployed configuration side by side with anothercardiovascular flow assist device 401 in the collapsed, deliverableconfiguration. The cage support members 420 of the deployed device 400are seen in their fully expanded state, exposing the pump and helicalpump blades 404. The cage support members 421 of the collapsed device401 are seen in their fully compressed state, collapsed toward thecenter of the device and coming to rest in contact with one another.

As can be seen in FIGS. 4A and 4B, the diameter of the device 400 whenin the expanded configuration, particularly the diameter of the cage, islarger than the diameter of the device 401 when in the collapsedconfiguration. There are different sized devices for different sizedaortas. The impeller (rotatory portion) is also sized corresponding toeach different sized device. The surface area of the impeller itselfdetermines its efficacy—the larger the surface area of the impeller, themore efficient it is at pumping blood. The cage is sized accordingly sothat it can be placed over the impeller.

Some embodiments of the impeller of the present specificationincorporate a blade skeleton comprising a plurality of morphedmicrocells each having a substantially hexagonal shape and comprised ofa shape memory alloy such as Nitinol. A thin layer of silicone is coatedover the hexagonal microcells and in the space or area within eachhexagon to complete the blade structure. As the blade of the impeller iswrapped around an inner shaft of the impeller in the collapsedconfiguration, the microcells are reshaped by tessellations, allowingfor tight compression of the blade about the shaft. In embodiments, eachside of each hexagon comprises an ‘S’ or dollar sign shape to impartincreased flexibility to the blade such that it is more easily deformed.Since the width and thickness of each skeleton junction are equal, thedeformation of the blade skeleton in a collapsed configuration isdistributed by wrapping around said impeller shaft. The hexagonalpatterns are preferred due to their efficiency in changing the shape ofthe blade as the device moves from a collapsed configuration to anexpanded configuration, although other polygonal patterns are possible,such as trigonal, tetragonal, pentagonal, heptagonal, octagonal,enneagonal and other shapes. In a hexagonal grid, each skeletalcomponent is the smallest it can possibly be, while the area of theblade skeleton is the largest it can possibly be, and the area is filledwith the fewest number of hexagons in the impeller structure. Thehexagonal shape provides for the greatest flexibility and deformabilitywhile requiring the least amount of material and therefore the leastweight. The impeller design, in accordance with the present embodiments,assures the lowest mass of the blade which is directly related to themotor torque requirement.

An optimal torque can be obtained for the device 400 by determining aratio of the diameter of the device 400 and the length of the device400. Because the diameter is fixed for each device size, the variablefactor for achieving optimal torque is device length. In embodiments, alonger motor length corresponds to a stronger motor. In embodiments,device 401 when in the collapsed configuration is 30-35% the size ofdevice 400 when in the expanded configuration.

As can also be seen in FIGS. 4A and 4B, the length of the device 400when in the expanded configuration is shorter than the length of thedevice 401 when in the collapsed configuration. In one embodiment, thelength of the device 400 when in the expanded configuration is in therange of 20 mm to 90 mm. In one embodiment, the length of the device 401when in the collapsed configuration is in the range of 30 mm to 100 mm.

An inner shaft portion and various outer shaft portions that are used tomount the blades 404 are proportioned to be as small in diameter aspossible. In an embodiment, the inner shaft portion and various outershaft portions together span a diameter of 2 mm. In an embodiment, theblades 404 are wrapped on the outer shaft portions in a closed form. Invarious embodiments, the diameter of the device 400 in the expandedconfiguration is in the range of 15 mm to 30 mm. In various embodiments,the diameter of the device 400 in an expanded configuration is in therange of 18 mm to 24 mm. In some embodiments, the diameter of the device401 in the collapsed configuration is in the range of 3 mm to 8 mm. Inone embodiment, the diameter of the device 400 in the expandedconfiguration is 18 mm, while the diameter of the device 401 in thecollapsed configuration is 6 mm.

In one embodiment, a motor having a diameter of 5 mm is positionedwithin a housing having a diameter of 6 mm. In this embodiment, animpeller opens to a diameter of 15 mm and a cage opens to a diameter of18 mm. In an expanded configuration, the cage has a diameter having arange of 16 mm, 17 mm, and up to 18 mm. In another embodiment, a motorhaving a diameter of 6 mm is positioned within a housing having adiameter of 7 mm. In this embodiment, an impeller opens to a diameter of18 mm and a cage opens to a diameter of 21 mm. In the expandedconfiguration, the cage has a diameter having a range of 19 mm, 20 mm,and up to 21 mm. In yet another embodiment, a motor having a diameter of7 mm is positioned within a housing having a diameter of 8 mm. In thisembodiment, an impeller opens to a diameter of 22 mm and a cage opens toa diameter of 25 mm. In this embodiment, in an expanded configuration,the cage has a diameter having a range of 22 mm to 23.5 mm and up to 25mm. In still another embodiment, a motor having a diameter 7 mm ispositioned within a housing having a diameter 8 mm. In this embodiment,an impeller opens to a diameter of 24 mm and a cage opens to a diameterof 28 mm. In the expanded configuration, the cage has a diameter havinga range of 26 mm, 27 mm, and up to 28 mm. In some embodiments, anddiscussed subsequently with reference to FIGS. 20A and 20B, a secondanchoring cage is added outside the device 400/401. The total diameterof the device 400/401 with the second anchoring cage may increase byapproximately 4 mm. Therefore, in some embodiments, the total outerdiameter of the device in the expanded configuration is 32 mm.

FIG. 5A is a side view illustration of one embodiment of thecardiovascular flow assist device 500 in the expanded, deployedconfiguration, depicting two cage support members 520 removed fromeither side of the helical screw pump 503. The end cap (not shown) hasalso been removed from the device 500 pictured in FIG. 5A. Thesecomponents have been removed to provide enhanced visualization of thehelical screw pump 503 of the device 500. In one embodiment, the helicalscrew pump 503 comprises an elongate, cylindrical inner shaft portion511, a distal outer shaft portion segment 512, four outer shaft portionblade attachment segments 514, five outer shaft portion spacer segments513, and a proximal outer shaft portion segment 516. The pump 503 isconnected at its proximal end, via a coupling 507, to a motor 509. Inone embodiment, motor 509, coupling 507 and inner shaft 511 aremanufactured as a single component. In one embodiment, the coupling 507is a low friction flexible coupling which transfers rotation from themotor 509 to the shaft. The coupling 507 acts to keep the motor 509 andshaft in alignment and prevents binding and stoppage of the motor 509.In the pictured embodiment, the pump 503 includes two sets of helicalblades 504. Each outer blade attachment segment 514 of the pump 503shaft includes two attached blades 504 positioned 180 degrees apart oneither side of said segment 514. Each of the two blade sets comprisesfour separate blades 504. In various embodiments, the pitch of eachblade in the deployed configuration is within the range of 20 to 70degrees. In one embodiment, the pitch of each blade in the deployedconfiguration is 45 degrees. The blades 504 in each set join to form acontinuous helical screw spiraling around either side of the pump 503.Having two sets of blades 504 improves performance of the pump byincreasing pumping efficiency and by balancing the pump 503. Inaddition, having the pump blades formed in segments eases collapsibilityand allows for intended deformation to create the smallest outsideprofile for minimally invasive intravascular insertion. In oneembodiment, each blade 504 includes a multitude of fenestrations 505 toincrease flexibility of the blades for compression and expansion. In oneembodiment, the blades 504 are coated in silicon to prevent blood flowthrough the fenestrations 505.

In one embodiment, the inner shaft portion 511 of the pump extendsthrough to the coupling 507 and is slidably movable within the pump'souter shaft portion segments 512, 514, 513, 516. This allows the deviceto lengthen and shorten during compression and expansion respectively.In one embodiment, the distal end of the inner shaft portion 511 of thepump 503 and the distal ends of the cage support members 520 attach tothe distal end cap (not shown). To lend linear stability to the device500, in one embodiment, the inner shaft portion 511, distal outer shaftportion segment 512, outer shaft portion blade attachment segments 514,and proximal outer shaft portion segment 516 are composed of stainlesssteel. In one embodiment, the outer shaft portion spacer segments 513are composed of silicon to absorb pressure during compression andexpansion of the device 500. As mentioned earlier, the blades 504 arecomposed of a shape memory metal to allow for compression and expansionof said blades 504. In one embodiment, the shape memory metal isNitinol. In one embodiment, the device 500 includes a Teflon motor seal.

FIG. 5B is an oblique, side view illustration of one embodiment of anouter shaft portion blade attachment segment 514, with one attachedblade 504, of the cardiovascular flow assist device. In one embodiment,each blade 504 is laser welded to each segment 514 at two points 517along the outer circumference of the segment 514, with a gap 518 inbetween the two weld points 517. The gap 518, along with thefenestrations 505 in the blade 504, lends greater flexibility to theblade 504 to ease blade compression and expansion.

FIG. 6A is an oblique, front view illustration and FIG. 6B is a sideview illustration of one embodiment of the helical screw pump 603 of thecardiovascular flow assist device, depicting two sets of helical blades604 in the expanded configuration. The distal end cap and cage have beencompletely removed to enhance pump 603 visualization. In the embodimentdepicted in FIGS. 6A and 6B, the pump 603 does not include a couplingand the entirety of the motor 609 can be seen. Also visible are theinner shaft portion 611, distal outer shaft portion segment 612, outershaft portion blade attachment segments 614, outer shaft portion spacersegments 613, and proximal outer shaft portion segment 616.

FIGS. 7A, B, and C are oblique front, side, and front-on viewillustrations respectively, of one embodiment of the helical screw pump703 of the cardiovascular flow assist device, depicting one set ofhelical blades 704 in the expanded configuration. The distal end cap andcage have been completely removed to enhance pump 703 visualization.Referring simultaneously to FIGS. 7A and 7B, the pictured embodiment ofthe pump 703 does not include a coupling and the entirety of the motor709 can be seen. Also visible are the inner shaft portion 711, distalouter shaft portion segment 712, outer shaft portion blade attachmentsegments 714, outer shaft portion spacer segments 713, and proximalouter shaft portion segment 716. FIG. 7C illustrates how each blade 704meets the other to form a virtually seamless helical screw.

FIGS. 8A, 8B, and 8C are oblique front, side, and front-on viewillustrations respectively, of one embodiment of the helical screw pumpof the cardiovascular flow assist device, depicting one set of helicalblades in the collapsed configuration. The distal end cap, cage,coupling, and motor have been completely removed to enhance pump 803visualization. Referring simultaneously to FIGS. 8A and 8B, the innershaft portion 811, distal outer shaft portion segment 812, outer shaftportion blade attachment segments 814, outer shaft portion spacersegments 813, and proximal outer shaft portion segment 816 are allvisible. FIG. 8C illustrates how each blade 804 compresses in toward thebody of the pump shaft while in the collapsed configuration.

FIG. 9A is an oblique, front view illustration and FIG. 9B is a sideview illustration of one embodiment of two cage support members 920formed together into a singular cage arm 950 in the expandedconfiguration. Referring simultaneously to FIGS. 9A and 9B, while in theexpanded configuration, the two cage support members 920 of each cagearm 950 are expanded outward from the pump (not shown) and from oneanother. At the distal end of each cage arm 950, the two support memberscome together in the form of a distal quarter-circle 951. At theproximal end of each cage arm 950, the two support members come togetherin the form of a proximal quarter circle 958 with attached elongatelinear member 959. In one embodiment, four cage arms 950 are circularlyarranged around the helical screw pump (not shown) of the device to formthe basket-like cage support structure. The four distal quarter-circles951 are attached to the distal end cap (not shown) and inner shaftportion (not shown) of the pump at the distal end of the device. Thefour proximal quarter-circles 958, with attached elongate linear members959, are attached to a housing (not shown) supporting the motor (notshown) at the proximal end of the device.

FIG. 9C is a top-down view illustration of the same embodiment of twocage support members 920 formed together into a singular cage arm 950 inthe expanded configuration of FIG. 9A. In one embodiment, the central,thin rectangular shaped portion 921 of each cage support member 920 iscomposed of stainless steel. In this embodiment, the rigidity of thisportion 921 lends stability to the device. In another embodiment, thecentral, thin rectangular shaped portion 921 of each cage support member920 is composed of a shape memory metal. In one embodiment, the shapememory metal is Nitinol. In this embodiment, the flexibility of thisportion 921 allows the cage to fit more snugly within the aorta. Thisportion 921 comes to rest against the inner wall of the aorta when thedevice is deployed. Distal and proximal to each central portion 921 aretwo hinge portions 922 and 924 respectively. Each hinge portion 922, 924is composed of a shape memory metal and allows for compression andexpansion of each cage support member 920. In one embodiment, the shapememory metal is Nitinol. In one embodiment, the distal end 923 andproximal end 925 of each support member 920 are composed of stainlesssteel. This again lends overall stability to the device and allows forattachment of the support members 920 to the other components of thedevice. In one embodiment, each elongate linear member 959 is composedof stainless steel.

In one embodiment, each hinge portion 922, 924 includes at least oneslit 926 to enhance flexibility and for the passage of a wire leadingfrom a sensor positioned distally on the device. Additionally, in oneembodiment, each hinge portion 922, 924 includes an elongate tubularmember 927 along its external edge for the guiding of sensor and/orcamera wires. In one embodiment, each central rectangular portion 921includes an elongate tubular member along one side for the guiding ofsensor and/or camera wires.

FIG. 9D is a front-on view illustration of the same embodiment of twocage support members 920 formed together into a singular cage arm 950 inthe expanded configuration of FIG. 9A. Visible in FIG. 9D are the slits926 and elongate tubular members 927, 928 for the passage of sensorand/or camera wires.

FIGS. 10A, 10B, and 10C are oblique front, side, and front-on viewillustrations respectively, of one embodiment of four cage arms 1050combined together to form a complete basket-like cage 1060 in theexpanded configuration. In various other embodiments, the cage includesfewer or more than four arms and takes on a variety of other shapes,including, but not limited to, an ellipse or a trapezoid. Referringsimultaneously to FIGS. 10A and 10B, each cage arm 1050 comprises twocage support members 1020 and one elongate linear member 1059. Thecomplete cage 1060 comprises four cage arms 1050 arranged together suchthat the distal ends of each cage arm 1050 come together to form acircle 1062 at the distal end of the device. The distal end of the cage1060 is attached to the distal end cap (not shown) and inner shaftportion at the circle 1062. The four elongate linear members 1059enclose a housing at the proximal end of the device and are spaced apartfrom one another in 90 degree increments. In one embodiment, the housingcontains the motor to drive the device and a battery to power the motor.In addition, in one embodiment, the housing includes a locking mechanismto couple with the positioning shaft. In the expanded configuration, theeight central rectangular portions 1021 of each cage support member 1020are expanded out away from the center of the device and from oneanother. FIG. 10C illustrates the circle 1062 formed at the distal endof the cage 1060 by the combination of four cage arms 1050.

FIGS. 11A, 11B, and 11C are oblique front, side, and front-on viewillustrations respectively, of one embodiment of four cage arms 1150combined together to form a complete basket-like cage 1160 in thecollapsed configuration. Referring simultaneously to FIGS. 11A and 11B,each cage arm 1150 comprises two cage support members 1120 and oneelongate linear member 1159. The complete cage 1160 comprises four cagearms 1150 arranged together such that the distal ends of each cage arm1150 come together to form a circle 1162 at the distal end of thedevice. The distal end of the cage 1160 is attached to the distal endcap (not shown) and inner shaft portion (not shown) at the circle 1162.The four elongate linear members 1159 enclose a housing (not shown) atthe proximal end of the device and are spaced apart from one another in90 degree increments. In the collapsed configuration, the eight centralrectangular portions 1121 of each cage support member 1120 arecompressed in toward the center of the device and are in contact withone another. FIG. 11C illustrates the circle 1162 formed at the distalend of the cage 1160 by the combination of four cage arms 1150.

FIG. 12A is a side view illustration on one embodiment of an arterialclosure device 1200, depicting the arterial closure discs 1205, 1210 ofthe device 1200 positioned within a delivery sheath 1220. The arterialclosure device is used to seal the arteriotomy site after insertion orretrieval of the pumping device of the present specification. In oneembodiment, the closure device 1200 includes a pair of opposing umbrellashaped discs 1205, 1210. The distal disc 1205 includes a concave-convexdeployed shape wherein its inner concave surface contacts the inner wallof the artery and the proximal disc 1210 includes a concave-convexdeployed shape wherein its inner concave surface contacts the outer wallof the artery. The discs 1205, 1210 are connected at their centers by adiaphragm 1207 having a lumen. Both discs 1205, 1210 are initiallyconstrained inside an elongate delivery sheath 1220, having a lumen andproximal and distal ends, and are deployed and expanded by extendingdistally from the distal tip of the delivery sheath 1220.

The delivery sheath 1220 includes a delivery sheath head 1222 at itsproximal end and handles 1227 along its length. The delivery sheath head1222 includes a distal end that attaches to the proximal end of thesheath and a proximal end. The delivery sheath head 1222 and handles1227 are used by the physician to manipulate the closure device 1200during placement. The delivery sheath 1220 includes an elongate bloodreturn tube 1224 having a proximal end and a distal end. The distal endof the blood return tube 1224 is positioned at the distal end of thedelivery sheath 1220 and the proximal end of the blood return tube 1224exits at a point between the distal and proximal ends of the deliverysheath 1220. The closure device 1200 includes a tamper tool 1230 forextending the discs 1205, 1210 beyond the distal end of the deliverysheath 1220. The tamper tool 1230 comprises an elongate shaft having atamper tool lumen, a proximal end, and a distal end and extends withinthe lumen of the delivery sheath 1220. The distal end of the tamper tool1230 abuts the proximal end of the proximal disc 1210. At its proximalend, the tamper tool 1230 includes a handle 1232 that extends beyond theproximal end of the delivery sheath head 1222. Positioned on the tampertool 1230 distal to the handle 1232 are a distal rivet 1235 and aproximal rivet 1237. During placement of the discs 1205, 1210 the distalrivet 1235 and proximal rivet 1237 sequentially engage a groove 1229positioned within the proximal end of the delivery sheath head 1222. Astring 1209 is attached to the distal disc 1205 and extends through thelumen of the diaphragm 1207, through the center of the proximal disc1210, and proximally through the tamper tool 1230 lumen.

During placement of the arterial closure discs 1205, 1210, the entiresheath system is advanced over the wire 1240 extending from the distalend of the pumping device. The wire 1240 extends through the tamper toollumen and guides the closure device 1200. If arterial closure is beingperformed after removal of the pumping device, a separate guide wire isfirst introduced into the artery. For arterial closure after theinsertion of the pumping device, the delivery sheath 1220 of the closuredevice 1200 is delivered through the existing arterial sheath used toinsert the pumping device.

FIG. 12B is a side view illustration of the same embodiment of thearterial closure device 1200 of FIG. 12A, depicting the distal arterialclosure disc 1205 expanded and deployed from the distal end of thedelivery sheath 1220. Once the distal end of the delivery sheath 1220 ispositioned inside the artery 1250, as confirmed by the presence of blood1255 at the proximal end of the blood return tube 1224, the distal disc1205 of the closure device 1200 is pushed out with the tamper tool 1230.Once beyond the distal end of the delivery sheath 1220, the distal disc1205 expands to its umbrella shape. The tamper handle 1232 is pusheddistally into the delivery sheath head 1222 until the distal rivet 1235engages the groove 1229, effectively locking the tamper tool 1230 inplace. The entire closure device 1200 is then pulled back so that theumbrella shaped distal disc 1205 opposes the hole in the artery from theinside. The existing arterial sheath for inserting the pumping device isthen removed and the delivery sheath 1220 is left just outside theartery 1250.

FIG. 12C is a side view illustration of the same embodiment of thearterial closure device 1200 of FIG. 12A, depicting both the distal 1205and proximal 1210 arterial closure discs expanded and deployed from thedistal end of the delivery sheath 1220. The reverse umbrella shapedproximal disc 1210 of the closure device 1200 is delivered to theoutside of the artery 1250 by simultaneously pulling back the deliverysheath 1220 and pushing in the tamper tool handle 1232 until thedelivery sheath head 1222 and tamper tool handle 1232 are fully apposed.In this position, the proximal rivet 1237 of the tamper tool 1230engages the groove 1229 of the delivery sheath head 1222, effectivelylocking the tamper tool 1230 in place. In one embodiment, the deliverysheath head 1222 is pushed distally along the delivery sheath 1220,wherein the delivery sheath 1220 includes a rivet 1225 that engages asecond groove 1221 within the delivery sheath head 1222, effectivelylocking the delivery sheath 1220 in place within the delivery sheathhead 1222. The delivery sheath 1220, with the delivery sheath head 1222,and the tamper tool 1230 are then removed.

FIG. 12D is a side view illustration of one embodiment of the arterialclosure discs 1205, 1210 fully deployed with the delivery sheathremoved. The distal disc 1205 is depicted within the artery 1250 and theproximal disc 1210 is depicted outside the artery 1250. The two apposingdiscs 1205, 1210 with center diaphragm 1207 seal the arteriotomy site.Once both discs 1205, 1210 are in place, the sheath and tamper arepulled out, exposing only the string 1209 attached to the distal disc1205. Once arteriotomy closure is confirmed, the string 1209 is cutbelow the skin. The guide wire in the center can be removed if necessaryfrom the center diaphragm 1207 keeping the artery 1250 sealed.

FIG. 12E is an illustration of one embodiment of the arterial closurediscs 1205, 1210, depicting the struts 1204 used to expand the discs1205, 1210 to their deployed configuration. The discs 1205, 1210 areconstricted and tubular shaped, as depicted in FIG. 12A, whenconstrained in the restraining sheath and expand into umbrella shapeddiscs 1205, 1210 outside the sheath, as depicted in FIG. 12E. Theproximal surface 1203 of the proximal disc 1210 indicates the pointwhere the tamper tool pushes on the discs to deploy them from thesheath. In one embodiment, the discs are made out of an expandable andbiocompatible material. The discs 1205, 1210 include a diaphragm 1207interconnecting them with a lumen 1208 in the center to accommodate thestring and guide wire exiting the artery. Each disc 1205, 1210 alsoincludes a hole at its center for accommodation of the string and guidewire. The radiating struts 1204 act to expand the discs into theirumbrella shape upon deployment.

FIG. 13 is a flowchart illustrating the steps involved in implanting thehemodynamic flow assist device in the descending aorta of a patient, inaccordance with one embodiment of the present specification. At step1302, a physician creates an access point in the femoral artery of apatient. A sheath with a guide wire is inserted into the femoral arteryand advanced such that the distal end of the sheath is positioned withinthe descending aorta at step 1304. Then, at step 1306, the hemodynamicflow assist device, in the collapsed configuration, is inserted into thesheath and is advanced along the guide wire. At step 1308, a positioningdevice attached to the proximal end of the flow assist device is used toadvance the flow assist device beyond the distal end of the sheath,causing the flow assist device to passively transform from its collapsedconfiguration into its expanded configuration. At step 1310, thepositioning device is used to position the flow assist device within thedescending aorta. The positioning device is then uncoupled from the flowassist device at step 1312. At step 1314, the positioning device andsheath with guide wire are removed from the patient. The access point isthen closed at step 1316.

FIG. 14 is a flowchart illustrating the steps involved in closing anarterial access point using the arterial closure device, in accordancewith one embodiment of the present specification. At step 1402, aphysician inserts a guide wire into the artery through the access point.The proximal end of the guide wire is inserted into the lumen of thetamper tool and the closure device is advanced along the guide wire atstep 1404. The distal end of the closure device is positioned in theinterior of the artery at step 1406. Then, at step 1408, the handle ofthe tamper tool is pushed to advance the distal disc beyond the distalend of the sheath, causing the distal disc to passively transform fromits compressed configuration into its expanded configuration within theartery. At step 1410, the closure device is pulled back to position thedistal disc against the inner wall of the artery. Then, at step 1412,the handle of the tamper tool is pushed to advance the proximal discbeyond the distal end of the sheath, causing the proximal disc topassively transform from its compressed configuration into its expandedconfiguration outside the artery. The closure device and guide wire arethen removed from the patient at step 1414.

A variety of optional components may be used or implemented with each ofthe aforementioned embodiments. Those optional components includesensors, cameras, modified cage sizes, different energy management orbattery charging systems, removability features, migration prevention,and positioning components.

Sensors and Camera(s)

Referring back to FIG. 1, in an embodiment, at least one of sensors 132,134, and 136 includes an accelerometer. The accelerometer is configuredto detect increased movement by the patient, signifying increasedphysical activity. The accelerometer generates data indicative of thephysical activity of the patient, and, based on the heightened physicalactivity, the device increases blood flow to meet demands. In anembodiment, the accelerometer generates data indicative of physicalactivity, such as walking or climbing stairs and transmits that data toa controller, which is in data communication with the pump. Thecontroller uses data from the accelerometer to manipulate the rotationalspeed of the rotating pump shaft of cardiovascular flow assist device100 in the expanded, deployed configuration. Conversely, if theaccelerometer detects decreased physical activity, such as sitting orlaying down, the controller will cause the pump to slow down and,accordingly, the device will decrease blood flow.

In another embodiment, the device includes a flow meter. In anembodiment, the flow meter is a MEMS sensor. In an embodiment, referringto FIG. 1, at least one of sensors 132, 134, and 136, include the flowmeter. In some embodiments, four sensors 134 towards the distal end andfour sensors 136 towards the proximal end of the device are flow meters.In an embodiment, the flow meter detects surface tension of the blood,which provides fluid velocity. In one embodiment, the surface tensiondata is used to measure pressure of the flow of blood. Informationpertaining to the fluid velocity and a size of the cage is used toderive a cross-section of the device. The presence of four sensors oneach end (distal and proximal) of the device enables recreating athree-dimensional (3D) image of the events that occur at each port ofthe diameter of the aorta. In one embodiment, the flow meter sends datato the patient via the cable attached to the proximal end of the device.Data collected by the flow meter(s) in combination with otherinformation, such as the dimensions of the device and the velocity ofblood, may be used to calculate a volume (in liters per minute) totitrate.

In an embodiment, the flow meter generates data indicative of thephysical activity of the patient, and, based on the heightened physicalactivity, the device increases blood flow to meet demands by increasingthe rotational speed of the rotating pump shaft. The flow metergenerates data indicative of physical activity, such as walking orclimbing stairs and transmits that data to a controller, which is indata communication with the pump. The controller uses data from the flowmeter to manipulate the rotational speed of the rotating pump shaft ofcardiovascular flow assist device 100 in the expanded, deployedconfiguration. Conversely, if the flow meter detects decreased bloodflow, which may occur when a person sits or lays down, the controllerwill cause the pump to slow down and, accordingly, the device willdecrease blood flow.

In an embodiment, at least one of sensors 132, 134, and 136, includes anEKG sensor. The EKG sensor measures cardiac electrical potentialwaveforms (voltages produced during the contraction of the heart). Theelectrical activity of the heart that is measured by the EKG sensor maybe used to detect instances of cessation of heartbeats. In anembodiment, device 100 delivers an electric shock when the EKG sensorindicates instance of cessation of heartbeats, thus functioning as adefibrillator or as a pacemaker. In an embodiment, the heart activity isdetected by the EKG sensor on a beat-to-beat basis, which is recordedand/or monitored in real time. The real time feedback provided by theEKG sensor may be used to drive an algorithm that is, in turn, used tocontrol rotational speed of the rotating pump shaft of cardiovascularflow assist device 100 in the expanded, deployed configuration. Sensorinformation on heart's beat-to-beat basis, compared to informationpertaining blood flow of the patient, helps overcome challenges inunderstanding depletion in blood flow due to heart-related diseasesversus Von Willebrand factor.

In an embodiment, distal end cap 106 includes at least one camera. Inone embodiment, the camera is positioned proximate the distal end of thedevice. In one embodiment, the camera is an infra-red (IR) chargedcoupled device (CCD) camera. Each camera positioned on distal end cap106 is accompanied with at least one light source to provide lightwithin the field of view of the camera. In an embodiment, the lightsource is a Light Emitting Diode (LED). Images captured by the cameraenable real-time viewing of the blood flow.

In an embodiment, the sensors 132, 134, 136, and camera(s) arecontrolled externally through an interface provided to the operator ofthe device. Sensor and camera wires connect the sensors 132, 134, 136,and camera(s), to the interface via patient cable 108.

Cage Size

In an embodiment, a mechanism is provided for changing a size of thecage based on the size of a patient's aorta. FIGS. 15A to 15E illustrateone embodiment of cardiovascular flow assist device 1500, at variousstages from an initial collapsed, deliverable configuration seen in FIG.15A, to various expanded, deployed configurations seen in FIGS. 15B to15E. As seen in FIG. 15A, cage support members 1520 of the collapseddevice 1500A are seen in their fully compressed state, collapsed towardthe center of the device and coming to rest in contact with one another.As can be seen in FIGS. 15A, 15B, 15C, 15D, 15E, the diameter of device1500B, 1500C, 1500D, and 1500E when in the expanded configuration,particularly the diameter formed by the cage support members 1520, islarger than the diameter of the device 1500A when in the collapsedconfiguration. As can also be seen in FIGS. 15A to 15E, the length ofthe device 1500B, 1500C, 1500D, and 1500E when in the expandedconfiguration is shorter than the length of the device 1500A when in thecollapsed configuration. Additionally, the length of device 1500E in themost-expanded configuration, is the shortest. The length of devices1500A to 1500E can be seen reducing as the device changes from thecollapsed configuration through various expanded configurations to themost expanded configuration (device 1500E). Distal end cap 1506 alsomoves with the expansion of the device from device 1500A to 1500E. EachFIGS. 15A, 15B, 15C, and 15D, provides a configuration that may beadapted for differently sized of aortas of different patients.Configuration of the device can be changed from one to another until asuitable configuration is achieved where the cage formed by the cagesupport members 1520 is able to fit snugly within the aorta.

As described previously in context of FIGS. 5A, 5B and 9A-D, a helicalscrew pump 1503 is connected at its proximal end, via a coupling 1507,to a first motor 1509. Operating the first motor 1509 drives theimpeller on pump 1503, causing rotation of blades 1504. In oneembodiment, the inner shaft portion 1511 of pump 1503 extends through tothe coupling 1507 and is slidably movable within the pump's 1503 outershaft portion segments. This allows the device 1500 to lengthen andshorten during compression and expansion respectively. The distal end ofthe inner shaft portion 1511 of pump 1503 and the distal ends of thecage support members 1520 attach to the distal end cap 1506. In anembodiment, a second pump is connected to the elongate linear members1559 attached to the four proximal quarter-circles formed by the pairsof cage support members 1520. The second pump is attached to theelongate linear members 1559 through a housing supporting the secondmotor at the proximal end of the device. As mentioned earlier, the fourto eight elongate linear members 1559 of the cage enclose a housing atthe proximal end of the device 1500 and are spaced apart from oneanother in 90 degree increments. The housing contains the second motor.In an embodiment, operation of the second pump drives the movement ofthe cage so as to move from a collapsed configuration to an expandedconfiguration, and vice-versa. Operation of the second pump enablesvariation in size of the device 1500, specifically variation in thediameter of the cage and the length of the device 1500. In anembodiment, a diameter of the cage is varied from collapsed to expandedconfigurations with three variable sizes: 18+/−2 mm, 21+/−2 mm, and24+/−2 mm, or any increment therein.

In embodiments, such as those described in context of FIG. 10, the cagesupport members 1520 of the device expand to form a basket-like cage inthe shape of a trapezoid, as seen in FIGS. 15B-15E. In various otherembodiments, the cage includes fewer or more than four support members1520 and takes on a variety of other shapes, including, but not limitedto, an ellipse.

In some embodiments, one or more sensors 1532 and 1534 located on distaland proximal hinged portions 1522 and 1524 of the cage support members1520 provide information about the size of the cage relative to walls ofthe aorta within which it is placed. In some embodiments, sensors 1532and 1534 are strain gauge sensors. In some embodiments, sensors 1532 and1534 are positioned at locations 1532 b and 1534 c respectively, whichcorrespond to a first location 1532 b at a first junction between distalhinge portion 1522 and a strut 1591 of support member 1520 and a secondlocation 1534 c at a second junction between the strut 1591 and proximalhinge portion 1524 of support member 1520. In some embodiments, datafrom sensors 1532 and 1534 is transmitted to a microprocessor of thedevice which is configured to calculate an angle at said first andsecond locations 1532 b, 1534 c to determine the shape and size of thecage. The microprocessor can then control a motor of the device toadjust the shape and size of the cage. In some embodiments, themicroprocessor and motor are contained within a housing at a proximalend of the device. In some embodiments, the housing has a diameter of 5mm. In some embodiments, at least one MEMS sensor shows the angle ofdisplacement of the cage within the aorta. The cage shape, size, andsymmetricity is monitored by strain cells or MEMS sensors embedded inany of the hinge portions 921, 922, 924 (described with respect to FIG.9C) and 1922, 1924 (described with respect to FIG. 19A). In someembodiments, the sensors are used to determine if the cage hassymmetricity and a trapezoidal profile.

In some embodiments, the first motor 1503 (shown in FIG. 15E) includes atachometer and a Hall Effect sensor (emag). The pressure and hall sensormeasurements indicate when the walls of the cage come in to contact withthe inner walls of the aorta, thereby providing a diameter of the cage.In embodiments, the first motor 1503 provides biofeedback when the cagetouches walls of the aorta and a resistance from the aorta is sensed.The first motor feedback is used to determine contact of the cage withthe aorta and to provide data on the size (diameter) of the cage in theexpanded configuration. A computing device is connected either through awire or wirelessly, to the first motor, so as to provide the informationabout the cage's expansion relative to aortic walls. As a result, theactive cage in accordance with embodiments of the present specificationcan be controlled to adjust according to aortic resistance. In oneembodiment, once aortic resistance is sensed, the memory shape of thecage goes back to 30% open. Beyond 30% opening, the cage may have toovercome the weakness of the shape memory alloy (Nitinol). The cage maybe further opened by controlling the cage through the second motor. Insome embodiments, the shape memory of the cage is responsible for theinitial opening of the cage and then the second motor is responsible foradjusting the cage size/opening in relation to aortic resistance. In thecompressed configuration, the cage members or components are aligned ina substantially linear shape. The inherent shape memory properties of ashape memory alloy, such as Nitinol, are preferable to cause the initialopening of the cage as an outside manipulative source, such as a motor,could cause the linear shape of the cage to buckle or bend duringopening. In certain embodiments, after the cage has opened to a certainpercentage, such as 30%, due to its shape memory property, a motor isused to fine-tune and adjust the size and shape of the opened cage.

FIGS. 15F, 15G, 15H, 15I, 15J, and 15K, illustrate the same embodimentof cardiovascular flow assist device 1500, at various stages fromexpanded, deployed configurations seen in FIG. 15F to a collapsedconfiguration seen in FIG. 15K. As seen from FIG. 15F to FIG. 15K, asthe device 1500 collapses, sensors on cage support members 1520 of thecage are able to detect proximity of the cage support members 1520 tothe impeller on the first motor 1503. In an embodiment, when cagesupport members 1520 of the cage touch the impeller, the first motor1503 is rotated backwards in order to move blades 1504 inwards. Asmentioned earlier, the blades 1504 are composed of a shape memory metalto allow for compression and expansion of blades 1504. In oneembodiment, the shape memory metal is Nitinol. Therefore, blades 1504that comprise the impeller, wrap about pump's 1503 outer shaft portionas the device collapses. Once the impeller has wrapped itself around theshaft of pump 1503, the device is considered to have reached itscollapsed state/configuration seen in FIG. 15K.

Self-Charging

As mentioned earlier, in an embodiment, the four elongate linear membersof the cage enclose a housing at the proximal end of the device and arespaced apart from one another in 90 degree increments. In oneembodiment, the housing contains the motor to drive the device and abattery to power the motor. The battery powers the motor that isattached to the proximal end of the first shaft for coaxially rotatingthe first shaft. The at least one set of collapsible blades also rotatewith the first shaft, to pump blood through the device. In anembodiment, the battery is a self-charging battery or inverter, whereinthe self-charging battery is charged by the unassisted flow of bloodturning the blades when a patient having the device implanted is in theresting or prone position.

In an embodiment, the battery is charged when the motor is not beingpowered by the battery. Specifically, in the resting or prone position,the motor is not being powered by the battery and the heart pumps theblood that causes the impeller to move. The blood may flow over theimpeller without creating resistance. Kinetic energy generated by themovement of the impeller is converted to electrical power that is usedto charge the battery. FIGS. 16A and 16B illustrate direction ofelectrical power that flows between the pump 1603 and battery 1635 atdifferent times. Electrical power flows in a direction 1636 from pump1603 to battery 1635 when the patient is in the resting position, orwhen the pump is not receiving power. Electrical power flows in adirection 1637 from battery 1635 to pump 1603 when the patient is awakeand/or moving. In an embodiment, body heat is used to charge thebattery. In another embodiment, a wireless Radio Frequency (RF) systemis embedded at the proximal end of the device to enable wirelesselectromagnetic powering of the device.

Migration Prevention

Embodiments of anchoring mechanisms are now discussed that preventmigration of the hemodynamic flow assist device in either the cranialdirection or the caudal direction.

In one embodiment, the cage of the hemodynamic flow assist device has acone shape configured to resist dislodgement within a patient's aorta.Dislodgement of the flow assist device may cause the device to move ormigrate within the aorta. Unintended migration, specifically caudalmigration, is prevented by a mechanism that anchors the device withinthe aorta. FIG. 17A illustrates an anchoring mechanism for a device 1700placed within an aorta 1740 in the form of a cone-shaped cage, inaccordance with an embodiment of the hemodynamic flow assist device ofthe present specification.

FIG. 17A also illustrates an additional anchoring mechanism where thecage of the hemodynamic flow assist device includes hooks 1752 on thedistal end of cage supporting members 1720 to resist dislodgement withinpatient's aorta 1740. In an embodiment, at least a pair of diametricallyopposing hooks 1752 are positioned on the outer wall of the cagesupporting members 1720 on the circumference of the cage. Each hook 1752is attached to cage supporting member 1720 at one end, and the other endprotrudes outwards, away from the cage, towards the inners walls ofaorta 1740.

FIG. 17B illustrates yet another embodiment of an anchoring mechanismwhere the proximal end of the hemodynamic flow assist device 1700includes a bifurcated anchor 1756 to resist dislodgement within apatient's aorta 1740. In one embodiment, the anchor 1756 is manufacturedusing a shape memory alloy, such as Nitinol. In other embodiments, theanchor 1756 is manufactured using any biocompatible metal. The anchor1756 may be attached to the proximal end of device 1700, such that theanchor 1756 bifurcates after inserting device 1700 in aorta 1750. In oneembodiment, a release mechanism is operated to enable bifurcation of theanchor 1756 once it is in the aorta 1750. Further, the anchor 1756 ispulled back such that it wedges against an aorto-iliac bifurcation 1754.Anchor 1756 may bifurcate, similar to the arms of a ‘V’ shape, to enableeach arm after bifurcation to respectively sit within each branch of anaortic bifurcation 1754. Aortic bifurcation 1754 could be an iliacbifurcation. As the forked anchor 1756 places each of its arms withinone branch of each bifurcated aorta 1754, the chances of caudalmigration of device 1700 are reduced.

Removable Pump

In cases, a physician may decide to allow the hemodynamic flow assistdevice to stay within the aorta for a longer duration. Patients withchronic conditions that require frequent assistance of cardiovascularflow assist devices may prefer to have a hemodynamic flow assist devicedeployed for a longer duration. However, devices that remain deployedfor a longer duration, such as for more than five weeks, remain incontact with blood vessels and walls of the aorta. It is likely thatwithin this period, tissues grow in to the cage of the device during itsdeployment, thus making it difficult to subsequently remove the device.

In an embodiment, the cage of the hemodynamic flow assist device can beseparated from the remaining components of the device. Consequently, thecage can be allowed to stay within the aorta, functioning as a stent,while the remaining components of the device are removed. In anembodiment, the pump(s), impeller, shaft, and the distal-end cap areremoved with the help of a sheath, while the cage remains at thedeployed location within the aorta in its expanded state.

FIGS. 18A and 18B illustrate the operation of exemplary engagement andrelease mechanisms to separate a cage 1821 from the remaining device, inaccordance with an embodiment of the present specification. Cage 1821 isformed by cage support members 1820. The engagement mechanism mayinclude one or more hooks that engage the pump with the cage 1821 whilethe release mechanism may include a device which interacts with saidengagement mechanism via the proximal end of the pump 1803 or cage 1821to disengage the engagement mechanism, disengaging and releasing thepump 1803 from the cage 1821. FIG. 18A illustrates the cage 1821 withinan aorta 1840 when the pump 1803 and other components of the device 1800are together. In one embodiment, the engagement mechanism is providedbetween the junction of the pump 1803 and the cage 1821 to allow forrelease of the pump 1803 from the cage 1821. FIG. 18B illustrates thecage 1821 within the aorta 1840 after the pump 1803 and other devicecomponents are withdrawn and removed. In embodiments, the other devicecomponents that are attached to the pump 1803 are removed with the pump1803. In the embodiment, the cage 1821 that remains behind in the aorta1840 functions similar to a stent.

FIGS. 19A, 19B, 19C, and 19D illustrate the operation of exemplaryengagement and release mechanisms. FIG. 19A illustrates an exemplaryembodiment of a cage formed by cage support members 1920, within anaorta, integrated with a pump 1903 and other various components of ahemodynamic flow assist device 1900. Cage support members 1920 encirclethe pump 1903. Cage support members 1920 comprise at least struts 1921and connectors 1942. Cage support members 1920 further include hingeportions 1922 and 1924, with a distal cap 1906 at the distal end 1910 ofdevice 1900, and with an inner shaft portion 1911 of the pump 1903 atthe proximal end 1912 of the device 1900. Struts 1921 are central, thinrectangular shaped portions with proximal and distal ends which linkthrough the distal and proximal hinge portions 1922 and 1924,respectively, to allow for compression and expansion of the cage supportmembers 1920. Connectors 1942 form a sinusoidal structure along thecircumference of the cage at both a distal end 1910 and a proximal end1912. The device includes both proximal and distal connectors 1942. Invarious embodiments, each of the proximal connectors 1942 comprises afirst end and a second end wherein said first end and second end aresecured to proximal ends of adjacent struts 1921. Each of said distalconnectors 1942 comprises a first end and a second end and said firstend and second end are secured to distal ends of adjacent struts 1921.The connectors 1942 are secured at a point on each side (distal andproximal) of each strut 1921 in a contiguous manner. In one embodiment,connectors 1942 are welded to the struts 1921. In an alternativeembodiment, the entire cage, including struts 1921 and connectors 1942,is laser cut from a single nitinol cylinder.

In embodiments, the struts 1921, hinge portions 1922 and 1924, andconnectors 1942 are manufactured using a shape memory alloy such asNitinol. In an embodiment, device 1900 comprises eight cage supportmembers 1920, which connect struts 1921 to the proximal and distal endseach with eight hinge portions 1924 and 1922, respectively, which arefurther connected with elongated portions of the cage support members1920. In an embodiment, the struts 1921 are discrete. In an embodiment,struts 1921 through hinge portions 1922 are welded to the distal end ofthe device 1900. In an embodiment, the struts 1921 through hingeportions 1924 are attached to a plate or a housing that encloses themotor of pump 1903 at the proximal end of the device 1900. In anembodiment, hinge portions are attached to the plate with a mechanicalbevel and repository attachment that links when compressed together, anddetaches when pulled apart.

In some embodiments, the release mechanism comprises a central releasemechanism within the inner shaft portion 1911 of the pump 1903 of thedevice 1900. The release mechanism may be controlled from a proximal endof the inner shaft portion 1911 of the pump 1903. FIG. 19B illustratesan exemplary embodiment of the device 1900 where the release mechanismis operated to release the cage support members 1920. The device 1900further includes one or more engagement mechanisms, comprising proximalcouplers 1944 and distal couplers 1946, that engage the pump 1903 withthe cage. In an embodiment, a release mechanism on the inner shaftportion 1911 is configured to interact with the couplers 1944, 1946 onthe cage support members 1920. In operation, the inner shaft 1911elongates and releases the proximal couplers 1944 and the distalcouplers 1946. In another embodiment, the struts 1921 are clipped withan engagement mechanism comprising a circular bevel in order to attachthem to the distal end of the device 1900. In one embodiment, theengagement mechanism further comprises a convex bevel on the outside ofthe proximal and distal ends of the struts 1921 which dislodges from aconcave repository in the inside of the proximal and distal caps whenthey are pulled apart due to an elongating inner shaft 1911. Inembodiments, the components of device 1900, excluding the cage supportmembers 1920, and including the pump 1903 and the distal end cap 1906,are connected to the inner shaft 1911. The release mechanism isactivated to disengage the engagement mechanism, disengaging andreleasing all of the components of the device 1900 from the cage supportmembers 1920 along with the shaft 1911. In other words, the struts 1921and hinge members 1922 and 1924 decouple from the inner shaft 1911 andthe components attached to the shaft 1911.

FIG. 19C illustrates an exemplary embodiment of the device 1900 wherethe releasing mechanism 1940 has separated the cage supporting members1920 from the remaining components of the device 1900. Once released,self-expanding nitinol struts 1921 and hinge members 1922, 1924 expandand contact the vessel wall like the rest of the cage. At this point,the connectors 1942, connecting struts 1921, also expand and begin tochange from a sinusoidal formation to a linear formation around cagesupporting members 1920.

FIG. 19D illustrates an exemplary embodiment of the cage supportingmembers 1920 that remains within the vessel. The inner shaft 1911, thepump 1903, and the remaining components of the device 1900 are pulledout along with the releasing mechanism. In some embodiments, the cagesupporting members 1920 are allowed to stay within the vessel for aperiod of 90 days. In some embodiments, the cage is allowed to staywithin the vessel for less than or more than 90 days and for a period upto six months. In embodiments, the self-expanding cage, post removal ofall the other components of the device 1900, expands to form a hollowcylinder that is positioned within the vessel and functions similar to astent.

In another embodiment, the device 1900 is positioned within a removablestent that was previously embedded within the aorta of a patient. FIG.20A illustrates an aortic stent 2070 with an engagement mechanismcomprising internal hooks 2072, in accordance with an embodiment of thepresent specification. The stent 2070 is positioned inside an aorta2040. In an embodiment, there are at least four hooks 2072, two each ona proximal and a distal end of the stent 2070. In alternativeembodiments, the numbers of hooks 2072 vary. FIG. 20B illustrates aretrievable pump device 2000 anchored within the aortic stent 2070 withinternal hooks 2072 of FIG. 20A, in accordance with an embodiment of thepresent specification. In one embodiment, the engagement mechanismfurther comprises recesses 2074 positioned on the retrievable pumpdevice 2000 which compliment hooks 2072 such that the retrievable pumpdevice 2000 engages and couples with the stent 2070 once positionedinside the stent 2070. In other embodiments, the attachment of theretrievable pump device 2000 to the inside of the aortic stent 2070 mayalso be accomplished by non-mechanical means, such as an engagementmechanism comprising positioning magnets of opposing poles positioned onthe stent and in the retrievable pump device. In embodiments, theretrievable pump device 2000 comprises the pump and the housing thatengages with the cage that was left to remain inside aorta 2040. Thehooks 2072 and recesses 2074 in the proximal and distal ends help engageand disengage the pump during insertion and removal from the aorta 2040.

Cage and Pump Occupying Only Partial Lumen in the Aorta

In cases, femoral access may be desired after embedding and deploying ahemodynamic flow assist device. However, presence of the device in theaorta may obstruct access by other medical devices such as catheters.

FIG. 21A illustrates an exemplary configuration of a hemodynamic flowassist device deployed in an aorta 2150 that allows access for otherdevices, in accordance with an embodiment of the present specification.A cage 2142A is configured with cage support members 2120A that are farapart in order to provide a large gap within cage 2142A. Cage 2142A isshaped asymmetrically so that device components within the cage arealigned on one side of the cage, leaving a gap on the other side forother medical devices to pass through.

FIG. 21B illustrates another exemplary configuration of a hemodynamicflow assist device deployed in aorta 2150 that allows access for otherdevices, in accordance with an embodiment of the present specification.The device and its cage 2142B are designed to align along one side ofthe longitudinal axis of aorta 2150. Cage support members 2120B aresymmetrically spaced around internal components of the device, includingthe pump(s) and the impeller. However, some of cage support members2120B are not in contact with the inner wall of aorta 2150. Distal endof the device is attached to a funnel 2144. A proximal end of funnel2144, which includes the narrow opening, may include a hook, or anyother attachment mechanism, that connects funnel 2144 to the device. Thedistal end of funnel 2144, which includes the broader opening, facesaway from the device. Opening at the distal end of funnel 2144 allowsaccess to other medical devices, through aorta 2150. In an embodiment,pump 2103 is operated at a relatively higher speed than the pumpdisclosed in alternative embodiments of the present specification. Inone embodiment, pump 2103 is operated at 10,000 RPMs. A higher speed ofpump 2103 may ensure that sufficient blood flow is maintained throughthe device, despite the device occupying only a fraction of aorta 2150along its longitudinal axis.

In an embodiment, the distal end of funnel 2144, with the broaderopening, is configured with a one-way flap, or a diaphragm that allowsfor movement in the proximal direction. The flap or the diaphragm willallow other medical devices to go through the funnel, but do not allowthe blood to flow through to the other side (distal) of theflap/diaphragm.

The above examples are merely illustrative of the many applications ofthe system of the present invention. Although only a few embodiments ofthe present invention have been described herein, it should beunderstood that the present invention might be embodied in many otherspecific forms without departing from the spirit or scope of theinvention. Therefore, the present examples and embodiments are to beconsidered as illustrative and not restrictive, and the invention may bemodified within the scope of the appended claims.

We claim:
 1. A retrievable intravascular hemodynamic flow assist devicecomprising: a pump comprising: a plurality of collapsible bladesattached to a rotatable shaft; and a motor configured to coaxiallyrotate said shaft; a collapsible cage enclosing said pump; and anengagement mechanism configured to engage said pump with said cage;wherein said device has a first diameter in an undeployed configurationand a second diameter in a deployed configuration, wherein the seconddiameter is greater than the first diameter, wherein said blades andsaid cage are positioned against said shaft when the device is in theundeployed configuration, and wherein said blades expand away from saidshaft and said cage expands away from said shaft to surround said bladeswhen the device is in said deployed configuration, and wherein saidengagement mechanism is configured to disengage said pump from saidcage, upon activation of a release mechanism, such that said pump iscapable of being retrieved from a blood vessel of a patient while saidcage remains within said blood vessel.
 2. The hemodynamic flow assistdevice of claim 1, wherein said engagement mechanism comprises at leastone hook.
 3. The hemodynamic flow assist device of claim 1, wherein saidengagement mechanism is provided at a junction of said pump with saidcage.
 4. The hemodynamic flow assist device of claim 1, wherein saidcage is configured to function as a stent after retrieval of said pump.5. The hemodynamic flow assist device of claim 1, wherein said cagecomprises a plurality of cage support members comprising a plurality ofstruts, proximal and distal hinge portions, and proximal and distalconnectors.
 6. The hemodynamic flow assist device of claim 5, whereineach of said plurality of struts is rectangular shaped and links one ofsaid plurality of proximal hinge portions with one of said plurality ofdistal hinge portions to allow for compression and expansion of saidcage as said device changes from said undeployed configuration to saiddeployed configuration.
 7. The hemodynamic flow assist device of claim5, wherein each of said plurality of proximal connectors comprises afirst end and a second end wherein said first end and second end aresecured to proximal ends of adjacent struts of said plurality of strutsand each of said plurality of distal connectors comprises a first endand a second end and said first end and second end are secured to distalends of adjacent struts of said plurality of struts to create acontiguous structure at a proximal end and a distal end of the cage. 8.The hemodynamic flow assist device of claim 6, wherein each of saidplurality of connectors is welded to each of said plurality of struts.9. The hemodynamic flow assist device of claim 6, wherein said pluralityof struts, proximal and distal hinge portions, and proximal and distalconnectors are laser cut from a single Nitinol cylinder.
 10. Thehemodynamic flow assist device of claim 5, wherein said cage compriseseight support members.
 11. The hemodynamic flow assist device of claim1, wherein said release mechanism comprises a central release mechanismpositioned within said shaft and is controlled from a proximal end ofsaid shaft.
 12. The hemodynamic flow assist device of claim 1, whereinsaid engagement mechanism comprises a plurality of proximal couplers anda plurality of distal couplers configured to secure said pump to saidcage.
 13. The hemodynamic flow assist device of claim 12, wherein saidshaft is elongated to release said plurality of proximal couplers andsaid plurality of distal couplers.
 14. The hemodynamic flow assistdevice of claim 5, further comprising a proximal cap and a distal cap,wherein said engagement mechanism comprises a plurality of convex bevelson an outer surface of proximal and distal ends of said struts which areconfigured to dislodge from a plurality of concave repositories insidesaid proximal and distal caps when said shaft is elongated.
 15. Thehemodynamic flow assist device of claim 1, further comprising at leastone sensor and a microprocessor, wherein said at least one sensor andmicroprocessor are configured to monitor data representative of a shapeand size of said cage in said deployed configuration and saidmicroprocessor is configured to control said motor to adjust a shape andsize of said cage based on said data.
 16. The hemodynamic flow assistdevice of claim 1 wherein said cage is configured to remain in a bloodvessel for a period up to six months after retrieval of said pump.
 17. Aretrievable intravascular hemodynamic flow assist device comprising: aretrievable helical screw pump comprising: a first shaft having a lumen,a proximal end, and a distal end, said first shaft comprising aplurality of blades forming a helical screw pump; a second shaft havinga proximal end and a distal end, wherein a portion of said proximal endof said second shaft is disposed within, and configured to telescopeinto and out of, a portion said lumen of said first shaft at the distalend of said first shaft; and a motor positioned at said proximal end ofsaid first shaft for coaxially rotating said first shaft and said bladesabout said second shaft to pump blood through the device; a cageenclosing said helical screw pump and comprising a plurality of cagesupport members; and an engagement mechanism configured to engage saidhelical screw pump with said cage; wherein said device has a firstdiameter in an undeployed configuration and a second diameter in adeployed configuration, wherein the second diameter is greater than thefirst diameter, wherein said plurality of blades and said plurality ofcage support members are positioned against said first shaft when thedevice is in the undeployed configuration, and wherein said bladesexpand away from said first shaft and said cage support members expandaway from said first shaft to form a cage surrounding said blades whenthe device is in said deployed configuration, and wherein saidengagement mechanism is configured to disengage said helical screw pumpfrom said cage, upon activation of a release mechanism, such that saidhelical screw pump is capable of being retrieved from a blood vessel ofa patient while said cage remains within said blood vessel.
 18. Aretrievable intravascular hemodynamic flow assist device comprising: aretrievable helical screw pump comprising: a first shaft having a lumen,a proximal end, and a distal end, said first shaft comprising aplurality of blades forming a helical screw pump; a second shaft havinga proximal end and a distal end, wherein a portion of said proximal endof said second shaft is disposed within, and configured to telescopeinto and out of, a portion said lumen of said first shaft at the distalend of said first shaft; and a motor positioned at said proximal end ofsaid first shaft for coaxially rotating said first shaft and said bladesabout said second shaft to pump blood through the device; a stentenclosing said helical screw pump; and an engagement mechanismconfigured to engage said helical screw pump with said stent, whereinsaid engagement mechanism is configured to disengage said pump from saidstent, upon activation of a release mechanism, such that said pump iscapable of being retrieved from a blood vessel of a patient while saidstent remains within said blood vessel.
 19. The hemodynamic flow assistdevice of claim 18, wherein said engagement mechanism comprises at leasta first hook positioned on a proximal end of said stent and at least asecond hook positioned on a distal end of said stent and wherein each ofthe at least one first hook and at least one second hook is configuredto engage with a plurality of recesses positioned in a proximal end ofthe helical screw pump and a distal end of the helical screw pumprespectively.
 20. The hemodynamic flow assist device of claim 18,wherein said engagement mechanism comprises a plurality of magnets ofopposing poles positioned on said stent and on said helical screw pump.